My Petrol Chainsaw will not tension the chain correctly

If the chain on your Qualcast PCS46Z petrol chainsaw will not tension correctly, the issue is usually related to incorrect adjustment procedure, a misaligned guide bar, or a tensioning mechanism that has not been fully engaged.

Incorrect chain tension can lead to poor cutting performance and safety risks, so it is important to set it correctly before use.

Quick Answer

If your chainsaw chain will not tension correctly:

• Ensure the chain brake is fully disengaged.
• Release the side cover adjustment knob.
• Use the tensioning wheel to adjust chain tightness.
• Turn clockwise to tighten and anti-clockwise to loosen.
• Re-secure the side cover by tightening the adjustment knob.
• Check that the chain lifts slightly from the guide bar but remains seated in the groove.

If the chain still will not adjust, the guide bar, chain or tensioning system may be worn or incorrectly fitted.

Before You Begin

Before adjusting the chain:

• Switch off the engine completely and allow it to cool.
• Remove the spark plug cap to prevent accidental starting.
• Place the chainsaw on a flat, stable surface.
• Wear protective gloves when handling the chain.

Correct chain tension is essential for safe operation and helps prevent chain derailment and excessive wear.

This guide applies specifically to the Qualcast PCS46Z model.

Steps

Step 1 – Disengage the Chain Brake

Ensure the chain brake is fully released before making any adjustments.

If the chain brake remains engaged, the chain will not move freely and correct tension cannot be set.

Step 2 – Release the Adjustment Knob

Locate the side cover adjustment knob.

• Pull out the adjustment knob lever.
• Turn it slightly anti-clockwise to loosen the side cover.

This allows the guide bar to move during tension adjustment.

Step 3 – Adjust the Chain Tension

Using the tensioning wheel:

• Turn clockwise to tighten the chain.
• Turn anti-clockwise to loosen the chain.

Continue adjusting until:

• The chain sits firmly in the guide bar groove.
• It can still be lifted slightly from the bar.
• It returns smoothly when released.

Do not overtighten the chain, as this can cause overheating and damage.

Step 4 – Secure the Side Cover

Once correct tension is achieved:

• Hold the guide bar in position.
• Tighten the adjustment knob to secure the side cover.

Ensure everything is firmly locked in place.

Step 5 – Final Check

After tightening:

• Rotate the chain by hand (wearing gloves).
• Confirm smooth movement around the guide bar.
• Check that tension remains stable after locking.

If the chain loosens after adjustment, repeat the process and ensure the guide bar is correctly seated.

Frequently Asked Questions

Why won’t my chainsaw chain tension properly?

Common causes include a partially engaged chain brake, incorrect use of the tensioning wheel, or a misaligned guide bar.

How tight should the chain be?

The chain should sit snugly in the guide bar groove but still be able to lift slightly and return into position.

Why does my chain loosen after tightening?

This can occur if the side cover is not fully secured, the guide bar is not seated correctly, or the chain has not fully engaged with the tensioning system.

Can a worn chain affect tensioning?

Yes. A stretched or worn chain may not hold correct tension and should be replaced if adjustment becomes difficult.

Is it safe to use the chainsaw if I cannot tension the chain?

No. An incorrectly tensioned chain can derail during use or cause damage to the guide bar and sprocket.