Husqvarna 525BX Workshop Manual page 50

Repair instructions
Insufficient 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. Recommended
max. speed exceeded.
Incorrect oil mixture in
the fuel.
Too low octane fuel
The piston ring starts to stick or is completely stuck
in its groove and has therefore not been able to
seal against the cylinder wall, which has resulted
in further, intensive temperature increases in the
piston
Seizure scores along the entire piston skirt on the
inlet and exhaust sides.
Cause:
Incorrect oil mixture in the fuel.
Too low octane fuel.
Air leaks
Cracked fuel hose.
Leaking inlet gaskets.
Cracked insulator or inlet manifold.
Air leakage in engine body.
Leaking crankshaft seals.
Leaking cylinder and crankcase gaskets.
Poor maintenance.
Dirty cooling fins on the cylinder.
Blocked air intake on the starter.
Blocked spark arrestor mesh in the muffler.
For the best results we recommend Husqvarna
two-stroke oil or ready-mixed fuel that is specially
developed for air-cooled two-stroke engines.
Mixing ratio: 1:50 (2%).
If Husqvarna two-stroke oil is not available another
good quality two-stroke oil can be used.
Mixing ratio: 1:33 (3%) or 1:25 (4%).
50
- English
Action:
Check and change the
carburettor setting.
Change the fuel.
Change to a higher
octane petrol.
Action
Change to a fuel with the correct oil mixture
Change to a fuel with the correct oil mixture.
Change to a higher octane petrol.
Replace damaged parts.
Replace leaking gaskets and shaft seals.
Clean the cooling fins and air intake.
Clean or replace the spark arrestor mesh.