SELVA MARINE DOLPHIN 15, Service Manual

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3-20
INSP
ADJ E
GENERAL
6. Measure:
9
Compression pressure
Too high
→
Inspect the cylinder head,
valve surfaces and piston crown for
carbon deposits.
Too low
→
Squirt a few drops of oil into
the affected cylinder and measure
again.
Refer to the following table.
Compression pressure
(With oil applied into cylinder)
Reading
Higher than
without oil
Same as
without oil
Diagnosis
Worn or damaged pistons
→
Replace.
Possible defective ring(s), val-
ves, cylinder head gasket or
piston
→
Repair.
Compression pressure:
961 kPa (9.8 Kg/cm 2 , 139.4 psi)
Measurement steps:
8
Crank the engine with the throttle wide-
open until the reading on the compres-
sion gauge stabilizes.
w
Before cranking the engine, ground all
spark plug leads to prevent sparking.
7. Install:
9
Spark plug