overheating 130 hp 3.0L Mercuiser

[siain]

weird problem on my 1988 mercuiser i/o, going along at a good clip (4000 rpm) and in about 5 min. the boat will slow down on its own (without me even touching the throttle) and i then watch the temp gauge go up into the red range. i put the boat in neutral and the temp will go back down in about 5 min. Now if i go 3000 rmp (10-15 mph) i can cruise around all day. any ideas about what is going on? (disclaimer) i am a new boater on an old boat and i am limited on my engine knowledge.

 

[Don S]

Re: overheating 130 hp 3.0L Mercuiser

Like any other overheat problem on a boat, the first thing you check is the impeller. To many ways for them to go bad, they are also a maintenace item and should be replaced everyother year to prevent problems before the happen.

 

[siain]

Re: overheating 130 hp 3.0L Mercuiser

impeller? a buddy of mine said thermostat, could that be it ( i hope so because i know how to change that)

 

[Fishermark]

Re: overheating 130 hp 3.0L Mercuiser

impeller? a buddy of mine said thermostat, could that be it ( i hope so because i know how to change that)

You could ask a hundred people and get a hundred different opinions. COULD it be the thermostat? Sure! If you know how to change that, go ahead and do it.

But to be honest, as Don says, the impeller is a regular maintenance item and you NEED to learn how to do that - or take your boat to a marine mechanic periodically.

(Oh yeah, I would say the chances are pretty high - like 95% that Don is right).

 

[Bondo]

Re: overheating 130 hp 3.0L Mercuiser

(Oh yeah, I would say the chances are pretty high - like 95% that Don is right).

Ayuh,....

Anytime there's an Overheat issue,.... The Impeller is the 1st place to Look.....