SERVICE MANUAL NUMBER 23
TROUBLESHOOTING
Water on Top of Pistons
Cause
Special Information
Operator shut engine off at high rpm
Engine “diesels” or tries to run backwards
Rain water running into flame arrestor
Spark plug misfiring
Poor fuel, high idle rpm, timing set too
high
Hatch cover
Improper combustion causes moisture in
the air to accumulate in the cylinder
Backwash through the exhaust system
Improper engine or exhaust hose
installation
Cracked exhaust manifold
Improper manifold to elbow gasket instal-
lation
Loose cylinder head bolts
Blown cylinder head gasket
Cracked valve seat
Check for warped cylinder head or
cylinder block
Check cylinder heads, cylinder block, and
intake manifold
Porous or cracked casting
Water in Crankcase Oil
Cause
Special Information
Boat has been submerged or bilge water
was high enough to run in through dipstick
tube
Water in boat bilge
Refer to “Water in Engine” (“On Top of Pis-
tons”)
Water seeping past piston rings or valves
Engine running cold
Defective thermostat, missing thermostat;
prolonged idling in cold water
Intake manifold leaking near a water pas-
sage
Check cylinder head, cylinder block, and
intake manifold
Cracked or porous casting
90-861326--1 MARCH 1999
Page 1C-23
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1998, 1999, 2000, 2001 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
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