Mercury 100 FourStroke, Service Manual

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90-830234R3 DECEMBER 1997 IMPORTANT INFORMATION - 1C-3
Detonation usually can be prevented if:
1. The engine is correctly set up.
2. Diligent maintenance is applied to combat the
detonation causes.
51115
Damaged Piston Resulting from Detonation
Following Complete
Submersion
Submerged While Running (Special
Instructions)
When an engine is submerged while running, the
possibility of internal engine damage is greatly in-
creased. If, after engine is recovered and with spark
plugs removed, engine fails to turn over freely when
turning flywheel, the possibility of internal damage
(bent connecting rod and/or bent crankshaft) exists.
If this is the case, the powerhead must be disas-
sembled.
Salt Water Submersion (Special
Instructions)
Due to the corrosive effect of salt water on internal
engine components, complete disassembly is nec-
essary before any attempt is made to start the en-
gine.
Fresh Water Submersion (Special
Instructions)
1. Recover engine as quickly as possible.
2. Remove cowling.
3. Flush exterior of outboard with fresh water to re-
move mud, weeds, etc. DO NOT attempt to start
engine if sand has entered powerhead, as pow-
erhead will be severely damaged. Disassemble
powerhead if necessary to clean components.
4. Remove spark plugs and get as much water as
possible out of powerhead. Most water can be
eliminated by placing engine in a horizontal posi-
tion (with spark plug holes down) and rotating fly-
wheel.
5. Pour alcohol into carburetor throats (alcohol will
absorbed water). Again rotate flywheel.
6. Turn engine over and pour alcohol into spark plug
openings and rotate flywheel.
7. Turn engine over (place spark plug openings
down) and pour engine oil into throat of carbure-
tors while rotating flywheel to distribute oil
throughout crankcase.
8. Again turn engine over and pour approximately
one teaspoon of engine oil into each spark plug
opening. Again rotate flywheel to distribute oil in
cylinders.
9. Remove and clean carburetors and fuel pump
assembly.
10. Dry all wiring and electrical components using
compressed air.
11. Disassemble the engine starter motor and dry the
brush contacts, armature and other corrodible
parts.
12. Reinstall spark plugs, carburetors and fuel pump.
13. Attempt to start engine, using a fresh fuel source.
If engine starts, it should be run for at least one
hour to eliminate any water in engine.
14. If engine fails to start, determine cause (fuel,
electrical or mechanical). Engine should be run
within 2 hours after recovery of outboard from
water, or serious internal damage may occur. If
unable to start engine in this period, disassemble
engine and clean all parts. Apply oil as soon as
possible.