MTD P90 series Shop Manual page 29

7. Compare the results to the following chart.
Leak-down Testing Results
Symptom
Air escaping from
the breather
Air escaping from
the exhaust
Air escaping from
the carburetor
Gauge reading
low
Gauge reading
moderate
Gauge reading
high
Possible cause
Worn cylinder or piston rings.
Possible blown head gasket
Leaking exhaust valve
Leaking intake valve
Cylinder and piston rings are in
good condition
There is some wear in the
engine, but it is still usable
excessive wear of cylinder and/
or piston rings. Engine should
be short blocked or it could be a
blown head gasket.
B T
ASIC ROUBLESHOOTING
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