Husqvarna 326R Workshop Manual page 42

Inlet side.
Particles of dust and dirt from carbon-like deposits
on the top of the piston and in the piston ring groove.
The piston ring sits firmly in the groove. Piston
material has been worn away.
The lower part of the piston skirt is thinner on the
inlet side than on the exhaust side.
The piston scored and worn from the piston ring down
on the inlet side.
Extensive damage to the lower part of the piston's
inlet side.
Cylinder and piston
Cause:
• Faulty air filter. Small dust particles
pass through the filter.
• The filter is worn out due to too
much cleaning, whereby small holes
have appeared in the material.
• Unsuitable filter maintenance, such
as wrong method or wrong cleaning
agent. Flock material becomes
loose and holes appear.
• Air filter incorrectly fitted.
• Air filter damaged or missing.
Larger, softer particles that penetrate into the engine cause damage to the piston
skirt under the piston ring as the illustration shows.
Cause:
• Air filter incorrectly fitted.
• Air filter damaged or missing.
Larger, harder particles that enter the engine cause serious damage to the under-
side of the piston skirt.
Cause:
• Air filter damaged or missing.
• Parts from the carburettor or intake
system have come loose and
entered the engine.
Action:
Fit a finer grade filter.
Check the filter carefully for holes and
damage after cleaning. Replace the
filter if necessary.
Clean more carefully and use the right
cleaning agent (such as tepid soapy
water).
Change the filter.
Fit the filter correctly.
Fit a new air filter.
Action:
Fit the air filter correctly.
Fit a new air filter.
Action:
Fit a new air filter.
Regular service and inspection.
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