TROUBLESHOOTING
SERVICE MANUAL NUMBER 24
Page 1C-26
90-861327--1 OCTOBER 1999
Water on Top of Pistons
Cause
Special Information
Operator shut engine off at high rpm
Engine “diesels” or tries to run backwards
Engine out of tune, poor fuel, high idle
rpm, timing set too high
NOTE: The term “diesel” refers to an engine’s tendency to run on after the key has been
turned to the OFF position.
Rain water running into flame arrestor
Hatch cover
Spark plug misfiring
Improper combustion causes moisture in
the air to accumulate in the cylinder
Backwash through the exhaust system
Improper engine or exhaust hose installa-
tion
Cracked exhaust manifold
Improper manifold to elbow gasket instal-
lation
Loose cylinder head bolts
Blown cylinder head gasket
Check for warped cylinder head or cylin-
der block
Cracked valve seat
Porous or cracked casting
Check cylinder heads, cylinder block, and
intake manifold
Water in Crankcase Oil
Cause
Special Information
Water in boat bilge
Boat has been submerged or bilge water
was high enough to run in through dipstick
tube
Water seeping past piston rings or valves
Refer to “Water on Top of Pistons”
Engine running cold
Defective thermostat, missing thermostat;
prolonged idling in cold water
Intake manifold leaking near a water pas-
sage
Cracked or porous casting
Check cylinder head, cylinder block and
intake manifold
Index