TROUBLESHOOTING
SERVICE MANUAL NUMBER 22
90-860074--1 FEBRUARY 2002
Page 1C-29
Engine Overheats
Cooling System
Cause
Special Information
IMPORTANT: The first step is to verify if the engine is actually overheating or if
the temperature gauge or sender is faulty
1. Seacock (seawater shut off valve)
partially or
fully closed (if equipped)
2. Low coolant level
3. Antifreeze incorrect type or not mixed
properly
3. Use low silicate type with special
additives
4. Loose or broken drive belt
5. Clogged or improperly installed sea
strainer
6. Loose hose connections between
seawater pickup and seawater pump
inlet
6. Pump will suck air; pump may fail to
prime or will force air bubbles into
cooling system
7. Seawater inlet hose kinked or
collapsed
7. Inlet hose must be wire reinforced to
prevent collapsing, and positioned to
prevent kinks or restrictions.
8. Seawater pickup clogged
9. Obstruction on boat bottom causing
water turbulence
9. Obstruction will be in front of seawater
pickup, causing air bubbles to be
forced into cooling system
10. Defective thermostat(s)
11. Exhaust elbow water outlet holes
plugged
12. Insufficient seawater pump operation
12. Worn pump impeller