Cleaning, Inspection; Analysis And Actions - Husqvarna 243RJ Workshop Manual

Small to medium size scores primarily
in the middle of the exhaust port.
Cylinder and piston

Cleaning, inspection

After dismantling, clean the individual components:
1. Scrape carbon deposits from the top of the piston.
2. Scrape carbon deposits from the cylinder's combustion chamber.
3. Scrape carbon deposits from the cylinder's exhaust port.
NOTE!
Scrape carefully with not too sharp a tool so as not to damage the soft
aluminium parts.
4. Wash all the components.
5. Inspect the different components for damage and wear.
Check the piston and cylinder for seizure damage and wear.
Also see the "Analysis and actions" section.
Check the piston ring for wear and damage.
Also see the "Analysis and actions" section.
Check the gudgeon pin.
– If it has blued, it must be replaced.
– If the piston moves too easily both the piston and the gudgeon pin must be replaced.
Check the needle bearing. If it is discoloured or damaged, it must be replaced.
Check the circlips. If they exhibit cracks or are discoloured (caused by overheating),
they must be replaced.

Analysis and actions

Experience tells us that piston or cylinder failure due to manufacturing errors are extre-
mely rare.
The reason is usually due to other factors, which is evident from the following.
Note the reasons for the breakdown, repair the damage and take the actions required to
prevent the same thing happening again.
Insuffi cient lubrication
The piston has small to medium size score marks usually in front of the exhaust port. In
extreme cases heat development can be so great that material from the piston smears
along the piston skirt and even in the cylinder bore.
Generally the piston ring is undamaged and moves freely in the ring groove
There can also be scores on the inlet side of the piston.
Cause:
• Incorrect carburettor setting. Recom-
mended max. speed exceeded.
• Incorrect oil mixture in the fuel.
• Too low octane fuel.
Action:
Check and change the carburettor setting.
Change the fuel.
Change to a higher octane petrol.
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