This article explains how to resolve common issues when the chain on your petrol chainsaw cannot be tensioned correctly.

⚠️ Safety Notice

Ensure the chainsaw is switched off and placed in a safe position before carrying out any adjustment.

Wear suitable protective gloves when handling the chain.

Important Information

Correct chain tension is essential for safe and effective cutting. The method for adjusting chain tension varies depending on the model of your chainsaw.

Please refer to your instruction manual for model-specific guidance.

For Sovereign / Challenge PCS38Z

This model uses bar nuts and an internal tensioning screw.

1. Disengage the chain brake.
2. Loosen the two bar nuts.
3. Ensure the tensioner pin is correctly located in the guide hole on the bar.
4. Use the internal tension screw to adjust chain tightness.
5. While holding the tip of the bar upward, tighten until the chain sits correctly in the guide bar channel.
6. The chain should lift slightly from the bar, allowing a single link to be pulled free.
7. Tighten the bar nuts securely and check chain movement.
8. Re-check tension and adjust if necessary.

If the Issue Persists

If you are still unable to tension the chain correctly after following the steps for your model, please contact our Technical Support Team for further assistance.

✔️ Summary

• Disengage chain brake before adjusting
• Use model-specific tensioning method
• Ensure chain lifts slightly from bar when correct
• Re-tighten all fixings securely

If fuel is leaking from the primer bulb on your lawnmower, this is usually caused by fuel backing up from the carburettor and escaping through the primer system.

Table of Contents

1. What Causes Primer Bulb Fuel Leaks?
2. The “Bleed & Tap” Procedure
3. Restarting the Machine
4. If the Problem Persists

What Causes Primer Bulb Fuel Leaks?

If fuel is coming out of the primer bulb, it typically indicates that:

• Fuel is overfilling the carburettor float chamber
• The float valve inside the carburettor is stuck open
• Fuel is being forced back through the primer line

In most cases, the issue is caused by a temporarily stuck float valve, which can often be resolved without replacing parts.

The “Bleed & Tap” Procedure

This simple procedure helps release pressure from the carburettor and free a stuck float valve.

Step 1 – Locate the Carburettor

Find the carburettor on the engine.

It is a metal component approximately the size of a fist, located between the air filter and the engine block.

Step 2 – Loosen the Float Chamber Nut

You will see two main nuts on the carburettor:

• One at the bottom
• One positioned at an angle (approximately 45°)

Using a suitable spanner, carefully loosen the angled nut.

Important: Do not fully remove the nut.

Step 3 – Bleed Excess Fuel

Allow fuel to drain from the loosened nut for approximately 20–30 seconds.

This relieves pressure and clears excess fuel from the carburettor chamber.

Step 4 – Re-Tighten the Nut

Once fuel has stopped draining:

• Retighten the angled nut securely
• Ensure it is properly sealed, but do not overtighten

Step 5 – Tap the Carburettor Float Chamber

Using a spanner, screwdriver handle, or similar tool:

• Gently tap the float chamber area of the carburettor a few times

This helps free the internal float valve if it is sticking.

Restarting the Machine

Once the procedure is complete:

1. Attempt to start the lawnmower as normal.
2. Prime the engine if required.
3. Check for any further fuel leakage from the primer bulb.

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. XSZ40E Specific Procedure
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.

XSZ40E Specific Procedure

On the XSZ40E model, the blade adapter consists of two parts:

• A disc pulley
• A T-shaped casting

These components interlock differently compared to standard models.

Step 1 – Position the Pulley

Lift the belt pulley up to the top of the crankshaft.

Step 2 – Align the Adapter

Insert the blade adapter into position, ensuring the two engagement clips are correctly aligned.

Rotate the assembly anti-clockwise to lock it into the belt pulley.

Step 3 – Secure the Assembly

Push the blade adapter and pulley assembly downward until fully engaged.

Step 4 – Fit the Blade

• Attach the blade to the adapter
• Tighten the blade bolt securely
• Confirm correct alignment and tightness

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 remove and replace the exhaust assembly on an SE475 engine.

Table of Contents

1. Tools Required
2. Removing the Exhaust
3. Replacing the Exhaust
4. Reassembling Components
5. Final Checks

Tools Required

• 10mm spanner or socket wrench

Removing the Exhaust

Step 1 – Remove Retaining Nuts

Locate the exhaust retention nuts.

• Undo the 2 x 10mm exhaust retention nuts
• These are typically positioned on the exhaust mounting points (see reference image markings)
• 

Step 2 – Remove the Exhaust Cover

Once the nuts are removed:

• Carefully take off the exhaust cover
• Place it safely to one side

Ensure no parts are damaged or dropped during removal.

Step 3 – Remove the Exhaust Assembly

With the cover removed:

• Carefully detach the exhaust assembly from the engine
• Set the exhaust assembly aside safely

Replacing the Exhaust

Step 4 – Fit the New Exhaust Assembly

Before installation:

• Check that the exhaust heat gasket is correctly positioned and undamaged

Then:

• Fit the new exhaust assembly into position on the engine
• Ensure it sits correctly and aligns with the mounting points

Step 5 – Refit the Exhaust Cover

• Place the exhaust cover back into its original position
• Ensure it aligns correctly with the mounting holes

Step 6 – Secure the Assembly

• Reinstall the 2 x 10mm nuts
• Tighten securely to ensure all components are firmly held in place

Do not overtighten, but ensure there is no movement in the assembly.

Final Checks

After installation:

• Confirm the exhaust is firmly secured
• Check that the gasket is seated correctly
• Ensure there are no loose parts or gaps
• Start the engine briefly to confirm normal operation