Jonsered 2036 Workshop Manual page 88

7
Small to medium sized scratches mainly opposite
exhaust port.
Medium sized to deep scratches along full piston
skirt on exhaust side.
Powerful scratches along the full piston skirt on
the exhaust side.
88
Cylinder and piston
Insufficient lubrication
The piston displays small to medium sized scratches usually opposite the exhaust port.
In severe cases the heat development can be so great that material from the piston
adheres along the piston skirt and also in the cylinder bore.
The piston ring is as a rule undamaged and can move freely in the piston ring groove.
Scratches may also be found on the piston's inlet side.
Reasons:
● Incorrect carburettor setting. Recom-
mended max. revs has been ex-
ceeded.
● Incorrect oil mixture in the fuel.
● Too low octane rating in the fuel.
The piston ring has begun to stick, or is completely stuck in its groove and has therefore
not been able to seal to the cylinder wall, which has resulted in an additional powerful
increase in heat in the piston.
Seizure scratches can be seen along the full piston skirt both on the exhaust side and
inlet side.
Reasons:
●
Incorrect oil mixture in the fuel.
● Too low octane rating in the petrol.
● Air leaks.
Cracked fuel pipe.
Untight inlet gaskets.
Cracked intermediate piece or inlet
pipe.
● Air leaks in engine body.
Untight crankshaft seals.
Untight cylinder and crankcase
gaskets.
● Unsatisfactory maintenance.
Dirty cooling fins on the cylinder.
Blocked air inlet on starter.
Blocked spark extinguishing net in
muffler.
For best results Jonsered two-stroke oil is recommended, which is specially developed
for air-cooled two-stroke engines.
Mixing ratio: 1:50 (2 %).
If Jonsered two-stroke oil is not available another high quality two-stroke oil can be
used.
Mixing ratio: 1:33 (3 %) or 1:25 (4 %).
Procedures:
Check and change the carburettor set-
ting.
Change fuel.
Change to petrol with high octane rating.
Measures:
Change to fuel with correct oil mixture.
Change to petrol with higher octane ra-
ting.
Replace damaged parts.
Replace untight gaskets and shaft seals.
Clean cooling fins and air intake.
Clean or change spark extinguishing net.