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
Water seeping past piston rings or valves
Engine running cold
Refer to “Water in Engine” (“On Top of Pistons”)
Defective thermostat, missing thermostat;
prolonged idling in cold water
Intake manifold leaking near a water passage
Cracked or porous casting
Check cylinder head, cylinder block, and intake
manifold
Engine Overheats (Mechanical)
Cause
Special Information
Engine RPM below specifications at wide-
open-throttle (engine laboring)
Damaged or wrong propeller; growth on boat
bottom;false bottom full of water
Wrong ignition timing
Timing too far advanced or retarded
Sticking distributor advance weights
Spark plug wires crossed (wrong firing order)
Lean fuel mixture
Refer to “Carburetor Malfunctions” in this section
Wrong heat range spark plugs
Exhaust restriction
Valve timing off
Jumped timing chain, or improperly installed
A blown head gasket(s) normally cannot be
detected by a compression check. Normally the
engine will run at normal temperature at low
RPM, but will overheat at speeds above 3000
RPM.
Blown head gasket(s)
Engines that are seawater cooled: Using a
clear plastic hose, look for air bubbles between
seawater pump and engine. If there are no
bubbles present, install clear plastic hose
between thermostat housing and manifold(s).If
air bubbles are present at a higher RPM, it is a
good indication there is a blown head gasket.
Defective oil pump, plugged oil passage, low oil
level
Insufficient lubrication to moving parts of engine
Index
1C-26 - TROUBLESHOOTING
90-823224--2 796
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you