Before operating your lawnmower, it is essential that you have read and understood the instruction manual supplied with your machine.

Quick Answer

To start a petrol lawnmower, you must check the oil and fuel levels, prime the engine if required, engage the safety/start lever, and pull the starter cord firmly. If the mower is difficult to start, the start cable tension may also need adjustment.

⚠️ Safety Notice

Before starting your lawnmower:

• Read and understand the instruction manual
• Wear suitable personal protective equipment (PPE)
• Operate on a clear, flat surface
• Keep children, pets, and bystanders away
• Handle petrol carefully — it is highly flammable

Failure to follow safety guidance may result in injury or damage.

Before You Start

Check the following before attempting to start the mower:

Engine Oil

• Ensure the engine contains the correct oil level
• Use the dipstick to confirm oil is between MIN and MAX marks
• Most mowers use SAE 30 oil (or equivalent), but always check your manual

Fuel

• Use fresh unleaded petrol (ideally less than 30 days old)
• Ensure the tank has sufficient fuel

Starting Your Petrol Lawnmower

Step 1 – Prime the Engine (If Fitted)

If your mower has a primer bulb:

• Press the primer bulb 3–4 times
• This helps fuel reach the carburettor for easier starting

If your model does not have a primer bulb, skip this step.

Step 2 – Position the Starter Cord

• Pull the starter handle gently
• Place it into the rope guide on the handlebar
• Ensure it is seated securely

Step 3 – Start the Engine

1. Pull and hold the engine brake/start-stop lever against the handle
2. Pull the starter cord sharply and smoothly
3. Repeat until the engine starts

Cold engines may require several pulls.

Once running, keep holding the brake lever while operating the mower.

Checking Start Cable Tension

A loose or incorrectly adjusted cable can prevent the engine brake system from engaging, resulting in starting issues.

Tools Required

• 10 mm spanner
• 13 mm spanner

Identifying a Loose Cable

Check the cable near the handle assembly:

• Excess slack or movement indicates adjustment is required
• The cable should be firm but not overly tight

Adjusting the Cable

Step 1

Locate the cable adjustment bolt on the handle.

Step 2

Loosen the locking nut using the spanners.

Step 3

Adjust the tension:

• Tighten or loosen until slack is removed
• Ensure the brake lever engages correctly when pulled

Step 4

Retighten the locking nut securely.

The correct position is typically mid-way along the threaded adjustment bolt.

Frequently Asked Questions

Why won’t my lawnmower start?

Common causes include:

• Old or stale fuel
• Low engine oil
• Incorrect priming
• Loose or faulty start cable

Do all lawnmowers have a primer bulb?

No. Some models start without priming and rely solely on the choke and fuel system design.

How many pulls should it take to start?

A cold engine may take several pulls. If it does not start after repeated attempts, recheck fuel, oil, and cable tension.

Can a loose cable stop the mower starting?

Yes. If the engine brake is not fully disengaging, the engine may not start or may immediately cut out.

Quick Answer

To assemble your petrol lawnmower handles, fit the lower handles into the mower chassis first, then assemble the upper handles using the bolt, washer, and quick-release clamp system. Correct orientation is essential to avoid cable tension issues and ensure safe operation.

⚠️ Safety Notice

Before starting:

• Ensure the mower is switched off and cannot start accidentally
• Work on a flat, stable surface
• Keep fingers clear of pinch points during assembly
• Do not force components into place

Incorrect assembly may affect safety controls and cable operation.

Before You Begin

• Lay out all parts before assembly
• Check that all bolts, washers, and clamps are present
• Refer to your model manual where available
• Identify upper and lower handle sections clearly

Most petrol lawnmowers use a similar handle assembly system, but small variations may apply.

Assembling the Upper Handles

Step 1 – Insert the Bolt

• Insert the bolt from the inside of the handle frame
• Ensure the bolt head sits against the inner tube of the handle

This provides correct clamping pressure when tightened.

Step 2 – Fit the Washer

• Place the washer onto the threaded end of the bolt (outside of the handle)
• Ensure it sits flat against the handle tube

Step 3 – Fit the Quick-Release Clamp

• Thread the quick-release clamp lever onto the bolt
• Tighten until the handle sections are firmly secured

Step 4 – Lock the Clamp

• Press the lever down into the locked position
• The upper handle should now be firmly attached to the lower handle

Connecting the Lower Handles to the Mower

Lower handle installation depends on model type:

Slot-In Design

• Insert lower handles into chassis mounting points
• Push firmly until fully seated
• Some resistance is normal

Bolted Design

• Align mounting holes with the mower chassis
• Insert bolts and tighten securely
• Do not overtighten

Ensuring the Handles Are Fitted Correctly

Correct alignment is essential for safe operation.

Cable Routing Check

When viewed from behind the mower:

• The engine brake/start-stop cable should run neatly down one side
• The self-propel cable (if fitted) should follow the same route
• Cables must not be twisted, stretched, or trapped

Control Check

Before use:

• Pull and release all control levers
• Ensure they move freely
• Ensure they return smoothly to the rest position

If controls feel tight or do not return properly, recheck handle alignment.

Troubleshooting

Handles feel loose after assembly

• Check quick-release clamp is fully locked
• Ensure washers are correctly fitted
• Confirm bolts are tightened properly

Cables feel too tight after assembly

• Handles may be fitted in the wrong orientation
• Check cable routing and alignment
• Ensure cables are not trapped under brackets or fixings

Quick-release clamp will not tighten

• Verify bolt is inserted from the correct side
• Check washer is in the correct position
• Ensure clamp lever is correctly threaded onto the bolt

Frequently Asked Questions

Why do my mower handles feel unstable after assembly?

This is usually caused by:

• Loose quick-release clamps
• Incorrect washer placement
• Bolts not fully tightened

Can I assemble the handles without tools?

Basic assembly can be done by hand, but some models may require a spanner to secure bolts properly.

Why are my control cables tight after assembly?

This is usually due to incorrect handle orientation, which places tension on the brake or drive cables.

What happens if I fit the handles the wrong way round?

Incorrect installation can:

• Prevent the engine brake from working correctly
• Cause self-propel cables to over-tension
• Affect safety and operation

Should I force the handles into place?

No. If parts do not align easily, recheck orientation and fixings. Forcing components can damage the frame or cables.

Quick Answer

If your self-propel system is not engaging properly, the most common cause is incorrect cable tension. The cable should have a small amount of free play (typically 5–10 mm). Too much slack will prevent the drive system from engaging correctly.

⚠️ Safety Notice

Before carrying out any checks or adjustments:

• Ensure the mower is switched off and cannot start accidentally
• Disconnect the spark plug cap where possible
• Keep hands away from moving parts
• Work on a flat, stable surface

Do not operate the mower with damaged cables or exposed drive components.

Visual Guidance

Please refer to the accompanying video for a visual demonstration of the cable adjustment procedure.

Understanding the Self-Propel System

The self-propel system works through several connected components:

• Self-propel drive cable
• Drive belt
• Gearbox and drive mechanism

If any of these components are worn, damaged, or incorrectly adjusted, the self-propel function may fail.

This guide focuses specifically on cable tension.

Checking the Self-Propel Cable

The self-propel cable runs from the handle lever down to the gearbox on the mower deck.

Step 1 – Inspect the Cable

• Locate the self-propel cable along the handle
• Check how much free movement (slack) is present
• Operate the self-propel lever and observe cable movement

Expected Tension

• 5–10 mm of free play = Normal
• More than 10 mm of free play = Likely too loose
• Very tight / no movement = Over-tensioned

If the cable is outside this range, adjustment is required.

Adjusting the Cable Tension

Step 1 – Locate the Barrel Adjuster

• Find the silver barrel adjuster along the cable
• This is usually positioned midway down the cable route

Step 2 – Loosen the Locking Nut

• Use the correct spanner (typically 8–12 mm depending on model)
• Loosen the locking nut at the top of the adjuster

Step 3 – Adjust the Cable

• Turn the barrel adjuster to reduce slack
• Adjust gradually in small increments
• Check lever movement as you adjust

Aim for 5–10 mm of free play in the lever.

Step 4 – Secure the Adjustment

• Tighten the locking nut against the barrel adjuster
• Ensure the adjustment does not move when tightened

Step 5 – Test the Self-Propel System

• Operate the self-propel lever
• Check that the mower drives smoothly
• Ensure engagement is immediate and consistent

Additional Causes of Self-Propel Failure

If correct cable tension does not restore operation, check the following:

Drive Belt Issues

• Loose belt
• Worn belt
• Broken belt
• Belt slipped off pulley

Gearbox Problems

• Worn internal gears
• Seized drive mechanism
• Damaged drive pulley

Cable Damage

Inspect the cable for:

• Fraying
• Kinks or bends
• Rust or corrosion
• Broken inner cable

If any damage is found, the cable must be replaced.

Frequently Asked Questions

What is the correct self-propel cable tension?

Typically, the correct setting is 5–10 mm of free play at the control lever.

Why is my mower self-propel not engaging?

Common causes include:

• Loose cable tension
• Worn or broken drive belt
• Damaged gearbox components
• Stretched or frayed cable

Can I overtighten the self-propel cable?

Yes. Over-tightening can cause:

• Constant drive engagement
• Premature belt wear
• Increased strain on gearbox components

Do I need tools to adjust the cable?

Most models require a spanner (usually 8–12 mm) to loosen and tighten the locking nut on the barrel adjuster.

Quick Answer

If your self-propel system is not working correctly, the drive belt may be loose, worn, or not correctly tensioned. The belt should sit firmly on the pulleys with slight flexibility, and the gearbox tension spring must be correctly attached to maintain correct tension.

⚠️ Safety Notice

Before inspecting the drive belt:

• Switch off the mower and allow all moving parts to stop
• Remove the spark plug cap where possible
• Ensure the mower is on a stable, flat surface
• Keep hands clear of blades and pulley areas

Do not operate the mower with a damaged or loose drive system.

Understanding the Drive Belt System

The drive belt transfers power from the engine to the gearbox, enabling the self-propel function.

The system relies on:

• Drive belt
• Gearbox pulley
• Gearbox tension spring

The tension spring maintains correct belt tension. If it becomes loose or detached, the belt may slip or stop driving the mower.

Checking the Drive Belt

Tools Required

• No tools required for basic inspection
• Pliers may be required if the tension spring needs reattaching

Step 1 – Locate the Drive Belt

The drive belt runs between:

• Blade adaptor under the mower deck
• Gearbox pulley on top of the gearbox assembly

Step 2 – Check Belt Tension

With the engine off:

• Press the belt gently sideways
• A small amount of movement is normal
• The belt should remain seated on both pulleys

If the belt moves excessively or feels loose, tension may be incorrect.

Step 3 – Inspect Belt Condition

Check the full visible belt for signs of wear:

• Cracks
• Fraying
• Splitting
• Glazing or polishing
• Excessive wear

If any damage is present, the belt should be replaced.

Checking the Gearbox Tension Spring

The gearbox tension spring keeps the belt under correct tension during operation.

Step 1 – Inspect the Spring

Ensure the spring is:

• Securely attached at both ends
• Not stretched or distorted
• Free from damage or corrosion
• Not obstructed by debris

If the Spring Is Detached

If the spring has come loose:

• The belt may slip off the pulley
• The self-propel system may fail to engage

Reattach the spring securely before use.

If the spring is missing or damaged, it must be replaced.

Common Faults

Belt Has Slipped Off the Pulley

This may be caused by:

• Detached or loose tension spring
• Worn or stretched belt
• Incorrect installation

Belt Is Damaged

A worn belt may:

• Slip under load
• Reduce drive performance
• Stop the self-propel system working completely

Replacement is recommended.

Spring Is Missing or Broken

Without the tension spring:

• The belt cannot maintain correct tension
• The self-propel system will not function properly

Frequently Asked Questions

How tight should the drive belt be?

The belt should be firm on the pulleys but still have slight flexibility when pressed. It should not feel loose or overly tight.

What happens if the drive belt is loose?

A loose belt may:

• Slip under load
• Reduce or stop self-propel function
• Cause poor drive performance

Can I reuse a worn drive belt?

No. If the belt shows cracks, fraying, or glazing, it should be replaced.

Why does my belt keep coming off?

Common causes include:

• Missing or detached tension spring
• Worn belt
• Misaligned pulleys

Do I need tools to check the belt?

Basic inspection can be done without tools, but pliers may be required if the tension spring needs reattaching.

Quick Answer

If your self-propel system is not working, the cable may be detached from the gearbox actuation lever. To fix this, you need to reconnect the cable end (spring hook) to the gearbox lever and ensure the outer cable is correctly seated in its housing. If the hook is broken, the cable will need replacing.

⚠️ Safety Notice

Before carrying out any inspection or repair:

• Switch off the mower and allow all moving parts to stop
• Remove the spark plug cap where possible
• Ensure the mower is stable on a flat surface
• Wear gloves when working near the gearbox and axle

Do not operate the mower if the cable is damaged or disconnected.

Understanding the Fault

The self-propel cable links:

• The drive lever on the handle
• The gearbox actuation lever at the base of the mower

If this connection fails, the self-propel system will not engage.

Common issues include:

• Cable has come loose from gearbox
• Spring hook at cable end has broken
• Cable has stretched or snapped
• Outer cable has slipped from its seating point

Inspecting the Cable

Step 1 – Check for Cable Slack

• Operate the self-propel lever
• Observe the cable movement along the handle and chassis
• If the cable remains loose or does not tighten, it may be disconnected or damaged

Step 2 – Inspect the Gearbox Connection

Locate the lower end of the cable at the gearbox.

Check for:

• Detached cable end
• Broken or bent spring hook
• Frayed or damaged inner cable
• Cable not seated in its guide

If the spring hook has failed, the cable must be replaced.

Replacing the Self-Propel Cable

⚠️ This procedure involves partial disassembly of the mower and should only be attempted if you are confident with mechanical repairs.

Step 1 – Remove the Wheels

• Remove the wheels required to access the axle assembly
• Keep all washers and retainers safely

Step 2 – Remove Axle Retainers

• Remove clips, springs, or brackets securing the axle
• Carefully note their positions for reassembly

Step 3 – Disconnect Cable from Gearbox

• Detach the cable end from the gearbox actuation lever
• Feed the cable back through the chassis grommet

Step 4 – Disconnect Cable from Handle

• Unhook the cable from the self-propel lever at the handle
• Remove cable fully from mower

Step 5 – Install Replacement Cable

Route the new cable through the same path as the original:

• Feed through chassis guides and grommets
• Attach inner cable hook to gearbox actuation lever
• Seat outer cable correctly in its housing point

Ensure the cable is not twisted or trapped.

Step 6 – Reassemble the Mower

Reinstall:

• Axle retainers and brackets
• Wheels
• Any covers or guards removed

After assembly:

• Operate self-propel lever
• Check smooth cable movement
• Confirm gearbox engagement works correctly

Important Information

• Many models use a combined self-propel and brake cable assembly
• Always ensure you order the correct cable for your specific model
• Incorrect routing can prevent the drive system from working properly

Guiding Photos

*Green ring is where the outer-cable needs to be situated, and the blue ring is where the hook at the end of the cable needs to be attached (the 'actuation lever'. The black spring here is the 'Gearbox tension spring' which hooks from the gearbox to the chassis/framework.*

*Corresponding blue & green circles for inner and outer cables*

Frequently Asked Questions

Why has my self-propel cable come off the gearbox?

Common reasons include:

• Cable stretch over time
• Vibration loosening the hook
• Worn or damaged gearbox lever
• Impact damage during use or maintenance

Can I just reattach a broken cable hook?

No. If the spring hook is damaged or deformed, the cable should be replaced for safety and reliability.

Why does my cable keep coming loose?

This may be caused by:

• Incorrect routing through chassis guides
• Missing retaining clips
• Excessive cable tension or wear

Do I need to remove the wheels to replace the cable?

Yes, on most models wheel and axle removal is required to access the gearbox connection point.

If your lawnmower's self-propel system is not working and you have already checked that the drive cable and drive belt are correctly fitted and functioning, the gearbox may be faulty.

Common gearbox faults include:

• Internal gear wear
• Damaged gearbox bearings
• Worn drive shafts
• Damaged gearbox pulleys
• Internal gearbox seizure

This guide explains how to replace the gearbox assembly.

Before You Begin

Important: Gearbox replacement is an advanced repair that requires a good level of mechanical knowledge and the use of specialist tools.

Before starting:

• Ensure the engine is switched off.
• Remove the spark plug cap.
• Work in a clean, safe environment.
• Wear appropriate personal protective equipment (PPE).

Replacing the Gearbox

Step 1 – Drain the Mower

Drain all fuel and engine oil from the machine.

Remove the air filter assembly if required for access.

Step 2 – Position the Mower

Carefully turn the lawnmower onto its side or upside down, ensuring all fluids have been removed first.

This will allow access to the drive system underneath the mower.

Step 3 – Remove the Wheel Covers

Using a suitable screwdriver, carefully remove the plastic wheel covers.

Step 4 – Remove the Axle Retaining Springs

Detach the retaining springs from both sides of the axle assembly.

Step 5 – Remove the Rear Wheels

Using a 13 mm spanner or socket:

1. Remove the wheel retaining nuts.
2. Slide the wheels from the axle.

Step 6 – Remove the Drive Gear Components

Using circlip pliers:

1. Carefully remove the circlip retaining the drive gear.
2. Remove the drive gear, drive pin, and any plastic wheel guards fitted to the axl

Step 7 – Remove the Gearbox Spring

Carefully detach the gearbox tension spring using pliers, a spring puller, or another suitable tool.

Note: The spring may be under tension and can be difficult to remove.

Step 8 – Remove the Drive Belt

Remove the drive belt from the gearbox pulley.

This may require carefully working the belt off the pulley by hand.

Step 9 – Remove the Gearbox Assembly

Once the spring and belt have been removed:

1. Lift the gearbox and axle assembly clear of the mower chassis.
2. Disconnect the gearbox cable fitting by compressing the retaining clips using long-nose pliers.
3. Pull the cable free from the gearbox.

The gearbox should now be completely detached.

Step 10 – Remove the Gearbox from the Axle

1. Remove the retaining circlips from both sides of the gearbox bushes.
2. Remove the gearbox bushes.
3. Carefully slide the gearbox from the axle.

The old gearbox can now be removed.

Step 11 – Install the Replacement Gearbox

Fit the new gearbox onto the axle and reassemble the mower by following the above procedure in reverse order.

Ensure:

• All circlips are securely installed.
• The drive belt is correctly seated.
• The gearbox spring is securely attached.
• The drive cable is connected correctly.
• All wheel fixings are tightened securely.

Final Checks

Before operating the mower:

• Refill with the correct engine oil.
• Refill with fresh petrol.
• Reinstall the air filter if removed.
• Reconnect the spark plug cap.
• Test the self-propel function in a safe area.

If your lawnmower engine repeatedly speeds up and slows down while running, this is commonly referred to as engine hunting.

This guide covers the most common causes and the checks you can perform to help resolve the issue.

What Is Engine Hunting?

Engine hunting occurs when the engine continuously increases and decreases its speed in a repeating cycle.

This is typically caused by a lean fuel mixture, meaning the engine is receiving too much air or not enough fuel.

Common causes include:

• Old or contaminated fuel
• Restricted fuel flow
• Dirty air filters
• Blocked carburettor jets
• Air leaks within the intake system

Initial Checks

Before inspecting the mower, consider the mowing conditions.

Grass Conditions

Very long, thick, or wet grass can place excessive load on the engine and may affect performance.

If possible:

• Cut long grass in stages.
• Avoid mowing excessively wet grass.
• Ensure the cutting height is set appropriately.

1. Check the Fuel

Old fuel is one of the most common causes of poor engine performance.

Ensure you are using:

• Fresh unleaded petrol
• Fuel that is no more than 30 days old

If the fuel is older than 30 days, it should be replaced.

2. Replace Old Fuel

Step 1 – Remove the Air Filter

Locate the air filter cover on the side of the engine.

Depending on your model:

• Unclip the cover, or
• Remove the retaining screw.

Remove the air filter.

Step 2 – Drain the Fuel

Remove the fuel cap and carefully empty the old fuel into a suitable approved container.

Dispose of old fuel responsibly in accordance with local regulations.

Step 3 – Reassemble

Refit the air filter and air filter cover.

Step 4 – Refill with Fresh Fuel

Fill the tank with fresh unleaded petrol.

3. Check the Air Filter

A blocked air filter can disrupt the air-to-fuel ratio and contribute to engine hunting.

Remove the air filter cover and identify which type of filter is fitted.

Sponge Air Filter

A clean sponge air filter is typically yellow or grey in colour.

Cleaning a Sponge Filter

1. Wash the filter in warm soapy water.
2. Rinse thoroughly.
3. Allow it to air dry completely.
4. Reinstall the filter.

Do not reinstall a wet filter.

Paper Air Filter

A clean paper air filter is usually white or off-white in colour.

Paper filters cannot be cleaned effectively.

If the filter is:

• Dirty
• Damaged
• Oil-soaked

It should be replaced.

If your petrol lawnmower is producing black smoke from the exhaust, the engine is typically running with too much fuel and not enough air. In most cases, this is caused by a dirty or blocked air filter restricting airflow to the engine.

This guide explains how to inspect and clean or replace the air filter.

Table of Contents

1. Common Cause of Black Smoke

2. Accessing the Air Filter

3. Sponge Air Filter

4. Paper Air Filter

Common Cause of Black Smoke

Black exhaust smoke is usually a sign that the engine is running rich, meaning the fuel-to-air ratio contains too much fuel.

The most common cause is a dirty air filter that restricts airflow into the engine.

Other symptoms may include:

• Reduced engine performance

• Increased fuel consumption

• Rough running

• Difficulty starting

Before investigating further, inspect the air filter and clean or replace it as necessary.

Accessing the Air Filter

Step 1 – Locate the Air Filter Cover

The air filter is typically housed behind a cover mounted on the side of the engine.

Depending on your model, the cover may be secured by:

• A clip-on cover, or

• A retaining screw

Step 2 – Remove the Cover

Carefully remove the cover and take out the air filter element.

Inspect the filter to determine whether it is a sponge filter or a paper filter.

Sponge Air Filter

A clean sponge air filter is generally yellow or grey in colour.

Inspect the Filter

Check the filter for:

• Dirt

• Grass debris

• Oil contamination

• Damage

Cleaning the Filter

1. Wash the sponge filter in warm soapy water.

2. Rinse thoroughly.

3. Allow the filter to air dry completely.

4. Reinstall the filter and refit the cover.

Important: Never reinstall a wet air filter, as this can affect engine performance.

Paper Air Filter

A clean paper air filter is typically white or off-white in colour.

Inspect the Filter

Check for:

• Dirt build-up

• Tears or damage

• Oil contamination

• Heavy discolouration

Replacing the Filter

Paper air filters cannot be effectively cleaned.

If the filter is dirty, damaged, or heavily discoloured, it should be replaced with a new filter.

Once replaced, reinstall the air filter cover securely.

If your petrol lawnmower is producing white, grey, or blue smoke from the exhaust, it is often caused by engine oil entering areas where it should not normally be present.

In many cases, the issue is temporary and can be resolved with a few simple checks.

Table of Contents

1. Common Causes of White, Grey, or Blue Smoke
2. Check the Engine Oil Level
3. Has the Lawnmower Been Tilted?
4. Allow Excess Oil to Burn Off
5. Check the Air Filter
6. Sponge Air Filter
7. Cartridge (Paper) Air Filter

Common Causes of White, Grey, or Blue Smoke

White, grey, or blue smoke is commonly caused by:

• Overfilled engine oil
• Oil spilled onto the engine or exhaust during maintenance
• The lawnmower being tilted incorrectly
• Oil entering the air filter housing
• A dirty or oil-soaked air filter

These issues can cause oil to burn during operation, resulting in visible smoke from the exhaust.

Check the Engine Oil Level

Before starting the engine, check the oil level.

Step 1 – Locate the Dipstick

Remove the oil filler cap and dipstick.

Step 2 – Check the Oil Level

Ensure the oil level is between the minimum and maximum marks on the dipstick.

For most petrol lawnmowers, the recommended oil is SAE 30 or an equivalent oil specified in the user manual.

Step 3 – Correct Any Overfilling

If the oil level is above the maximum mark, remove the excess oil before operating the machine.

Excessive oil can be forced into the combustion chamber or air intake system, causing smoke.

Has the Lawnmower Been Tilted?

If the lawnmower has recently been tipped onto its side, oil may have entered the exhaust, cylinder, or air filter housing.

This is one of the most common causes of temporary smoke.

Typical situations include:

• Cleaning underneath the mower deck
• Transporting the mower
• Performing maintenance

If this has occurred, the smoke will often clear after a short period of normal operation.

Allow Excess Oil to Burn Off

If the oil level is correct and the mower has been tilted recently:

Step 1

Start the engine in a safe, well-ventilated outdoor area.

Step 2

Allow the engine to run normally.

Step 3

Monitor the exhaust smoke.

As any excess oil burns away, the amount of smoke should gradually reduce and eventually stop.

Note: This process may take several minutes depending on how much oil has entered the exhaust or intake system.

Check the Air Filter

Oil contamination can sometimes affect the air filter, particularly if the mower has been tilted.

Remove the air filter cover and inspect the filter element.

Sponge Air Filter

A clean sponge air filter is generally yellow or grey in colour.

Cleaning a Sponge Filter

1. Remove the filter.
2. Wash it using warm soapy water.
3. Rinse thoroughly.
4. Allow it to air dry completely before refitting.

Do not reinstall a wet filter.

Cartridge (Paper) Air Filter

A clean paper air filter is usually white or off-white in colour.

Paper filters cannot be effectively cleaned.

If the filter is:

• Dirty
• Damaged
• Oil-soaked

It should be replaced.

If the pull cord on your petrol lawnmower is stuck or will not pull out, this is usually caused by either engine resistance, a mechanical blockage, or a fault within the starter system.

This guide covers the most common causes and the steps you can take to resolve the issue.

Table of Contents

1. Freeing the Engine from the Compression Stroke
2. Checking the Engine Oil Level
3. Clearing the Underside of the Deck
4. Checking Cable Tension
5. Inspecting the Self-Propel Drive Belt

Common Causes of a Stuck Pull Cord

The pull cord may become difficult or impossible to pull due to:

• Engine compression resistance
• Incorrect oil level (too low or too high)
• Blockages under the mower deck
• Incorrect cable tension affecting the engine brake
• A slipped or damaged drive belt
• Failure of the recoil starter mechanism

1. Freeing the Engine from the Compression Stroke

Tools Required

• Spark plug tool
• Protective gloves

If the engine stops in the compression stroke, the piston may resist movement, making the pull cord extremely difficult to operate.

Step 1 – Remove the Spark Plug Cap

Disconnect the thick black spark plug lead from the spark plug.

Step 2 – Remove the Spark Plug

Using a spark plug tool, carefully unscrew the spark plug anti-clockwise and remove it from the engine.

Step 3 – Release Engine Pressure

With protective gloves fitted:

1. Hold the engine brake/start lever on the handle.
2. Carefully rotate the blade by hand 4–5 times.

This helps release internal pressure and free the engine.

Step 4 – Reassemble

1. Reinstall the spark plug by hand to avoid cross-threading.
2. Tighten using the spark plug tool.
3. Refit the spark plug cap until it clicks into place.

You should now find the pull cord operates more freely.

2. Checking the Engine Oil Level

Incorrect oil levels can affect engine movement and starting.

Low Oil Level

If there is insufficient oil:

• Add the correct oil type (usually SAE 30 or as specified in your manual)
• Check the dipstick to ensure the level is between minimum and maximum marks
• Gently rotate the blade to confirm the engine moves freely

Overfilled Oil (Hydro-Lock Condition)

If too much oil has been added or the mower has been tipped, oil may enter the cylinder and prevent compression.

To resolve this:

1. Remove the spark plug cap.
2. Remove the spark plug.
3. Pull the starter cord several times to expel excess oil.
4. Clean and refit the spark plug.
5. Reinstall the spark plug cap.

3. Clearing the Underside of the Deck

Blockages beneath the mower can prevent the blade from rotating, which also prevents the engine from turning.

Check for:

• Thick grass build-up
• Twigs or debris
• Obstructions around the blade area

Clean thoroughly before attempting to start again.

Important: Always ensure the spark plug cap is removed before inspecting or cleaning underneath the mower.

4. Checking Cable Tension

If the stop/start (engine brake) cable is too loose, the brake may not fully disengage.

This can increase resistance when pulling the starter cord.

Ensure the cable is correctly adjusted according to your model’s starting or cable tension guide.

5. Inspecting the Self-Propel Drive Belt

If the drive belt has slipped or become misaligned, it may create resistance within the crank system.

Check that:

• The belt is correctly seated on the pulleys
• It is not damaged or stretched
• It has not slipped off the drive system

If necessary, refit the belt following the drive belt replacement instructions.

This guide explains how to check and adjust the start–stop (engine brake) cable tension on your petrol lawnmower. If this cable is incorrectly adjusted, the engine may fail to start or may not stop correctly.

Table of Contents

1. What the Start–Stop Cable Does
2. Signs of Incorrect Cable Tension
3. Tools Required
4. Checking Cable Tension
5. Adjusting the Cable
6. Final Checks

What the Start–Stop Cable Does

The start–stop cable runs from the control lever on the handle down to the engine.

Its function is to:

• Engage and disengage the engine brake
• Allow the engine to start when the lever is held
• Stop the engine when the lever is released

If the cable is not correctly adjusted, the engine may not operate as expected.

Signs of Incorrect Cable Tension

The cable may need adjustment if:

• The engine will not start
• The start lever feels too loose or unresponsive
• The engine does not stop correctly when the lever is released
• There is excessive slack in the cable

Tools Required

Depending on your model, you may need:

• 8mm and 10mm spanner
• or 10mm and 12mm spanner

Checking Cable Tension

Step 1 – Inspect Cable Slack

Check the amount of free movement in the cable.

If there is more than 5–10mm of play, the cable will need adjustment.

Step 2 – Locate the Adjuster

Find the silver barrel adjuster located approximately halfway along the cable.

This is the adjustment point for tensioning.

Adjusting the Cable

Step 1 – Loosen Locking Nut

• Use the correct spanner to loosen the locking nut at the top of the barrel adjuster
• Do not fully remove the nut

Step 2 – Adjust Cable Tension

• Turn the barrel adjuster to reduce cable slack
• Aim for approximately 5–10mm of free play in the cable

Adjust gradually and recheck movement as you go.

Step 3 – Secure the Adjustment

Once correct tension is achieved:

• Tighten the locking nut
• Fully secure the barrel using the appropriate spanners

Ensure nothing moves once tightened.

Final Checks

After adjustment:

1. Pull the start lever to confirm smooth operation
2. Check that the cable returns correctly when released
3. Attempt to start the mower to confirm correct function

Safety Information

Always ensure the engine is switched off before adjusting the cable.

Keep hands clear of moving parts, and ensure the mower is on a stable surface before carrying out any maintenance.

If your petrol lawnmower is vibrating excessively during use, this is usually caused by damage or imbalance in the cutting system. In most cases, this occurs after the blade has struck a hard object such as a tree root, paving slab, or drain cover.

This guide explains the most common causes and the checks you can carry out.

Table of Contents

1. Common Cause of Excessive Vibration
2. Blade Adaptor Inspection
3. Blade Inspection
4. Checking for a Bent Crankshaft

Common Cause of Excessive Vibration

Excessive vibration is most commonly caused by a blade strike, where the mower blade hits a solid object during operation.

When this happens, the engine may stop suddenly and force from the impact is transferred through the cutting system.

Typical causes of blade strike include:

• Tree roots
• Stones or rubble
• Drain covers
• Paving slabs
• Uneven ground

Blade Adaptor Inspection

The blade adaptor is designed to absorb impact and protect the engine from damage.

Check for the Following:

• Cracks in the cast aluminium body
• Chips or missing sections
• Missing shear pins
• Signs of deformation

Action Required

If the blade adaptor is:

• Cracked
• Chipped
• Missing shear pins
• Broken or deformed

It must be replaced before the mower is used again.

Operating the mower with a damaged adaptor may lead to further mechanical damage.

Blade Inspection

In more severe impacts, the blade itself may be damaged.

Check the Blade for:

• Bending or deformation
• Visible dents or warping
• Cracks or splits
• Uneven or asymmetrical shape

Identifying Damage

A damaged blade will often appear visibly uneven when rotated by hand.

Action Required

If any damage is found, the blade must be replaced immediately.

Do not attempt to straighten or repair a damaged blade.

Checking for a Bent Crankshaft

The most serious consequence of a blade strike is a bent crankshaft.

Symptoms of a Bent Crankshaft:

• Severe vibration during operation
• Uneven rotation of the blade
• Wobbling motion when the blade is turned by hand

How to Check:

1. Ensure the engine is switched off and the spark plug cap is removed.
2. Carefully rotate the blade by hand.
3. Observe the movement of the blade and drive shaft.

If the crankshaft is bent, the engine will not rotate smoothly.

Action Required

A bent crankshaft is a major engine fault.

In most cases, the engine will require replacement rather than repair.

This guide explains how to check the height adjustment system and ensure it is working correctly.

Table of Contents

1. How the Height Adjustment System Works
2. Checking the Adjustment Lever
3. Checking the Height Adjustment Spring
4. Inspecting the Connecting Rod

How the Height Adjustment System Works

Most petrol lawnmowers use a mechanical linkage system that adjusts the height of both front and rear wheels simultaneously.

This system typically includes:

• A height adjustment lever
• A spring-loaded locking mechanism
• A connecting rod between axles
• Front and rear axle mounting points

If any part of this system becomes loose, disconnected, or obstructed, the height adjustment may not function correctly.

Checking the Adjustment Lever

Step 1 – Test Full Movement

Operate the height adjustment lever through its full range of motion.

Move the lever forward and backward (or up and down, depending on model) and check for:

• Smooth movement
• Even resistance throughout the range
• No sticking or binding

Step 2 – Check Locking Action

Ensure the lever:

• Returns correctly into position
• Locks securely into the height selector teeth
• Does not slip out of position during use

If the lever does not lock properly, a missing or displaced spring may be the cause.

Checking the Height Adjustment Spring

The height adjustment spring helps maintain tension and ensures the lever locks into the correct position.

Inspection Steps:

• Check that the spring is present and correctly fitted
• Ensure it is not stretched, broken, or detached
• Confirm it is providing sufficient tension to hold the lever in place

If the spring is missing or damaged, it should be replaced before further use.

Inspecting the Connecting Rod

The connecting rod links the front and rear axle assemblies, allowing them to move together when adjusting cutting height.

Location

The rod is typically located along the side of the mower deck, often on the left-hand side, running between the front and rear axles.

What to Check

Ensure that:

• The connecting rod is securely attached at both ends
• The rod is not bent or damaged
• The front and rear axle connection points are intact

Connection Points

Check that:

• Cotter pins and spring clips are fitted correctly, or
• Bolts and nuts (depending on model) are tight and secure

If any of these components are missing or loose, the height adjustment system may not function correctly.

This guide explains how to safely remove the wheels from your petrol lawnmower. The exact method may vary depending on your model, so please follow the section that matches your machine.

Table of Contents

1. Front Wheels
2. Rear Wheels (XSZ41D, XSZ51C and Similar)
3. Rear Wheels (XSZ48A, XSZ53C and Similar)

Front Wheels

Step 1 – Remove the Wheel Trim / Hub Cap

Start by carefully removing the wheel trim (hub cap).

• Use a flat-head screwdriver or similar tool
• Gently lever the trim off
• If it is tight, work around the edge in multiple positions until it releases

Step 2 – Remove the Fixings

Once the hub cap is removed, you will see the retaining components.

Using a wrench or spanner:

• Remove the nut (47)
• Remove the washer (48)

The wheel should now come free from the axle.

Step 3 – Remove the Wheel

Carefully slide the wheel off the axle.

Be mindful of the internal components, including:

• Bearings (49)

These may remain in place or come away with the wheel.

Step 4 – Reassembly

To refit the wheel, repeat the process in reverse order, ensuring all components are correctly seated.

Rear Wheels (XSZ41D, XSZ51C and Similar Models)

Step 1 – Remove the Wheel Trim

Remove the hub cap as described in the front wheel section.

Step 2 – Remove the Wheel Fixings

Using a spanner:

• Remove the nut (47)
• Remove the washer (48)

Step 3 – Remove the Wheel

Take off the wheel carefully, ensuring you do not lose or damage:

• Bearings (49)
• Cog (58)
• Dust cover (51)

Step 4 – Remove the Circlip

Using suitable circlip or long-nose pliers:

• Remove the circlip (52)

This releases the drive cog (58) from the axle.

Step 5 – Reassembly

Refit all components in reverse order, ensuring:

• The cog is correctly seated
• The circlip is fully secured
• The wheel rotates freely after assembly

Rear Wheels (XSZ48A, XSZ53C and Similar Models)

Step 1 – Remove the Wheel Trim

Remove the hub cap as described previously.

Step 2 – Remove the Wheel Fixings

Using a spanner:

• Remove the nut (30)
• Remove the washer (42)

Step 3 – Remove the Wheel

Carefully remove the wheel, taking care not to lose the bearings (44).

Step 4 – Remove the Cog Gear Assembly

To remove the cog gear (46) and dust cover (48):

• Unscrew the three screws (47)
• Carefully remove the assembly from the wheel hub

Step 5 – Reassembly

Reassemble the wheel in reverse order, ensuring all fixings are secure and the wheel spins freely once refitted.

This guide explains how to safely remove and replace the cutting blade on a petrol lawnmower.

Table of Contents

1. Tools and Parts Required
2. Preparing the Lawnmower
3. Removing the Blade
4. Fitting the New Blade
5. Important Notes

Tools and Parts Required

Before starting, ensure you have the following:

• Thick protective gloves
• Socket wrench (appropriate size for blade bolt)
• New blade washer (recommended to replace the old washer)

Preparing the Lawnmower

Before carrying out any work:

1. Switch off the engine completely.
2. Remove the spark plug cap to prevent accidental starting.
3. Ensure the mower is on a stable surface.

Accessing the Blade

You can access the blade in one of the following ways:

• Tilt the mower backwards by lowering the handles (ideally with assistance), or
• Drain all fuel and oil, then carefully turn the mower upside down

Important: Ensure fuel and oil are fully drained before inverting the machine.

Removing the Blade

Step 1 – Secure the Blade

Wear thick gloves and firmly hold the blade to prevent it from rotating.

Step 2 – Loosen the Blade Bolt

Using a socket wrench:

• Turn the blade bolt anti-clockwise to loosen it

If the bolt is tight:

• Use a block of wood to stop the blade from turning, or
• Clamp the blade carefully to secure it in place

Step 3 – Remove the Blade

Once loosened:

• Remove the bolt and washer
• Take off the blade from the blade adaptor / boss / carrier

Fitting the New Blade

Step 1 – Inspect the Blade Adaptor

Check the blade adaptor for damage.

If it is cracked, worn, or damaged, it should be replaced before fitting a new blade.

Step 2 – Fit the New Blade

1. Position the new blade onto the adaptor.
2. Ensure the locating pins are correctly aligned.
3. Make sure the blade is seated securely and evenly.

Step 3 – Fit New Washer and Bolt

• Install a new washer (do not reuse the old one)
• Insert the blade bolt

Step 4 – Tighten the Blade Bolt

Using the socket wrench:

• Tighten the bolt clockwise
• Ensure it is securely fastened

Important Notes

• Always replace the washer when fitting a new blade
• Never operate the mower with a damaged or loose blade
• Ensure the blade is fitted in the correct orientation

If the Blade Bolt Will Not Loosen

If the blade bolt is stuck:

• Secure the blade using a block of wood
• Apply controlled force using the correct socket tool
• Avoid damaging the blade or adaptor

This guide explains how to replace the blade adapter (also known as the blade carrier or boss) on your petrol lawnmower.

Table of Contents

1. What Is the Blade Adapter?
2. Signs of a Damaged Blade Adapter
3. Replacement Procedure (Most Models)
4. Final Checks

What Is the Blade Adapter?

The blade adapter is a cast alloy component located above the lawnmower blade.

It connects the blade to the crankshaft and plays a key role in transferring power from the engine to the cutting system.

Importantly, the blade adapter also acts as a protective component. If the blade strikes a hard object, the adapter is designed to absorb impact and prevent damage to the engine.

If it becomes damaged, the blade may become loose and the mower may vibrate excessively.

Signs of a Damaged Blade Adapter

A faulty blade adapter may cause:

• Excessive vibration during use
• Loose or unstable blade fitting
• Visible cracks or fractures in the casting
• Uneven cutting performance

If the adapter is damaged, it must be replaced before the mower is used again.

In some cases, similar symptoms may indicate crankshaft damage, which is more serious and may not be repairable.

Replacement Procedure

Step 1 – Remove the Blade

Using a socket wrench or spanner:

• Loosen and remove the blade bolt
• Remove the blade from the adapter

Step 2 – Remove the Drive Belt (If Fitted)

If your model has a drive belt:

• Carefully remove the belt from the pulley section of the blade adapter

Step 3 – Locate the Parallel Key

Check for a parallel key located along the crankshaft.

This small metal key secures the adapter in position.

Ensure you do not lose it during removal.

Step 4 – Remove the Blade Adapter

Carefully pull the blade adapter off the crankshaft.

If resistance is felt, gently wiggle the adapter while pulling downward.

Step 5 – Fit the New Blade Adapter

1. Align the new adapter with the crankshaft.
2. Ensure the parallel key is correctly seated in position.
3. Push the adapter firmly into place.

Step 6 – Refit the Drive Belt

If applicable:

• Loop the drive belt back over the pulley section of the adapter

Step 7 – Refit the Blade

• Position the blade onto the mounting lugs at the base of the adapter
• Install the blade bolt
• Tighten securely using a socket wrench

Step 8 – Final Tightening Check

Ensure:

• The blade is firmly secured
• The adapter is fully seated
• No movement or wobble is present

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Final Checks

Before using the mower:

• Check that the blade is secure
• Ensure there is no wobble or movement
• Confirm the drive belt is correctly seated (if applicable)
• Verify smooth rotation by turning the blade by hand (with spark plug disconnected)

This guide explains how to replace or refit the drive belt on your petrol lawnmower. The drive belt is an essential part of the self-propel system and transfers power between the engine and gearbox.

In some cases, the belt may slip off during use or need to be removed when replacing components such as the blade or control cables.

Table of Contents

1. When to Replace the Drive Belt
2. Accessing the Drive Belt
3. Fitting the Drive Belt
4. Final Alignment and Tensioning
5. Additional Notes

When to Replace the Drive Belt

The drive belt may need attention if:

• The self-propel system is not working
• The mower is not driving forward correctly
• The belt has slipped off the pulleys
• The belt appears worn, cracked, or stretched

In many cases, the belt may simply need refitting rather than replacement.

Accessing the Drive Belt

On some models, access may be improved by removing the belt cover.

Optional Step – Remove the Belt Cover

• Locate the plastic belt guard between the blade and gearbox
• Remove the securing screws and fixing bolts
• Carefully lift off the cover

This will expose the drive belt and pulleys for easier refitting.

Fitting the Drive Belt

The drive belt connects between two main pulleys:

• Pulley A: Gearbox pulley (silver housing)
• Pulley B: Engine or blade drive pulley

Step 1 – Position the Belt on the Blade Area

• Feed the belt over the blade area first
• Do not fully seat it onto Pulley B at this stage

Step 2 – Route the Belt Through the Deck

• Feed the belt underneath the belt shield or mower body housing
• Ensure the belt is not twisted or trapped

Step 3 – Fit the Belt onto Pulley A

• Loop the belt around Pulley A (gearbox pulley)
• The gearbox may tilt slightly to provide tension—this is normal

Ensure the belt is fully seated in the pulley groove.

Step 4 – Align the Belt with Pulley B

• Position the belt in line with Pulley B
• Check that the belt is correctly routed and not misaligned

Step 5 – Seat the Belt onto Pulley B

• Rotate the blade carefully by hand (wearing gloves)
• Continue rotating until the belt “walks” itself onto Pulley B

The belt should settle smoothly into place without force.

Final Alignment and Tensioning

Once fitted:

• Check that the belt sits correctly in both pulley grooves
• Ensure there are no twists or misalignment
• Confirm the belt moves freely when the blade is rotated
• Refit the belt cover if it was removed

This guide explains how to check whether the spark plug on your machine is working correctly. If your engine will not start, the spark plug is one of the first components to inspect.

Table of Contents

1. Cleaning the Spark Plug
2. Tools Needed
3. How to Test the Spark Plug
4. Interpreting the Results
5. What to Do Next

Cleaning the Spark Plug

Before testing, inspect the spark plug for dirt or carbon build-up.

A dirty spark plug can prevent the engine from sparking correctly.

To clean it:

• Use a wire brush to remove carbon deposits
• Or wipe gently with a cloth lightly dabbed in petrol

Ensure the tip of the spark plug is clean before proceeding.

Tools Needed

• Spark plug wrench
  

How to Test the Spark Plug

Step 1 – Prepare the Area

Carry out the test in a shaded area so the spark is easier to see.

Step 2 – Remove the Spark Plug

1. Pull off the spark plug cap (thick black ignition cable).
2. Using a spark plug wrench, unscrew the spark plug anti-clockwise.
3. Remove it carefully from the engine.

Step 3 – Reattach to the Lead

• Insert the spark plug back into the cap/cable
• Allow it to hang securely from the lead

Step 4 – Earth the Spark Plug

• Press the metal threaded section of the spark plug firmly against a clean metal part of the engine
• This creates an earth connection for the test

Step 5 – Perform the Test

While holding the spark plug against the engine:

1. Hold down the start/stop lever on the handle
2. Pull the starter cord as if starting the engine

Interpreting the Results

Watch the tip of the spark plug closely:

• Bright white spark visible: Spark plug is working correctly
• No spark visible: Spark plug or ignition system may be faulty

What to Do Next

If the spark plug is not the cause of the issue, check the following:

• Fuel is fresh (less than 30 days old)
• Engine oil is at the correct level
• Air filter is clean and dry
• Starter cable is correctly tensioned

If No Spark Is Detected

If the spark plug does not produce a spark even after cleaning:

• The spark plug may need replacing
• If a replacement plug also does not spark, the ignition coil may be faulty

In this case, further technical support or repair may be required.

If your petrol-powered machine has been standing unused for a period of time, old fuel can cause starting and performance issues. Draining the carburettor and replacing the fuel with fresh petrol can often help resolve these problems.

Before You Begin

Safety Equipment

Before carrying out this procedure, ensure you:

• Wear appropriate personal protective equipment (PPE)
• Work in a well-ventilated area away from sources of ignition
• Keep naked flames, sparks, and cigarettes away from the work area

Tools Required

• 10 mm spanner or socket
• Metal container or fuel-safe collection tray
• Fresh petrol

Important: Ensure you have a suitable metal container positioned beneath the machine to safely collect any fuel that is drained.

Draining the Carburettor

Step 1 – Position the Collection Container

Place a metal container directly beneath the carburettor drain bolt to catch the fuel as it drains from the system.

Step 2 – Remove the Drain Bolt

Using a 10 mm spanner or socket, carefully loosen and remove the carburettor drain bolt by turning it anti-clockwise.

Step 3 – Allow the Fuel to Drain

Once the drain bolt has been removed, fuel will begin to flow from the carburettor.

Allow all fuel to drain into the collection container.

Note: If the fuel tank is full, fuel may continue to flow until the tank is empty.

Step 4 – Refit the Drain Bolt

Once the fuel has completely drained:

1. Reinstall the drain bolt.
2. Tighten it securely, taking care not to overtighten.

Step 5 – Dispose of Old Fuel Safely

Dispose of the drained fuel in accordance with local regulations.

Do not pour petrol down drains, onto the ground, or into household waste.

Refill with Fresh Fuel

Once the carburettor has been drained and the drain bolt has been securely refitted:

1. Fill the fuel tank with fresh petrol.
2. Prime the fuel system if your machine is fitted with a primer bulb.
3. Start the machine following the normal starting procedure.