Overheating

sanibelboater

Recruit
Joined
Jun 27, 2010
Messages
1
We have a Merc 150 hp outboard and today our engine started overheating and the alarm sounded. Turned off immediately and kept restarting to get back to boat ramp. Any ideas as to what is wrong?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Overheating

We have a Merc 150 hp outboard and today our engine started overheating and the alarm sounded. Turned off immediately and kept restarting to get back to boat ramp. Any ideas as to what is wrong?

Restricted water flow to the intakes
Blocked water intakes
Failed water pump impeller
Faulty thermostat/s
Faulty poppet valve
Blockage in the engine cooling passages
Faulty warning switch
Incorrect ignition timing

and the list goes on.

You need to do some proper diagnostics to get closer to the problem.
When was the water pump last serviced? If it's been more than 18 months, I'd start there. Then check the easy stuff, temp sensor, thermostats and poppet...

Chris...........
 
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