Overheating help!!!!!

Rumley

Petty Officer 2nd Class
Joined
Dec 5, 2009
Messages
105
Hi everyone,
i have a 1988 5.7L mercrusier with alpha one outdrive. i was out on the weekend for the 2nd ride (first ride was only around 20 mins when i put it in the water to bring it to camp). we were maybe 15 mins into a ride, first 5 mins was pretty close to WOT then i cut it down to 3200rpm. all of a sudden boat lost all power and stopped, i went to restart it and my 2 friends saw smoke coming out of the engine compartment, it was mainly steam but a little bit of smoke as well. there was some oil coming out of the valve covers so i am assuming that i am going to have to change those as well. when i was watching the temp gauge about a minute or 2 mins before it died on me it was still reading at 175. i changed the impeller before the season started. im going to check that impeller again. it looks like what killed the power was oil went into the ignition coil. the oil was bubbling and it had gotten so hot. im not really sure what would have caused this and what i should check first. after it had cooled down a few hrs later i tried to start it and it did fire up right away so i know that it isnt seized. Any help that anyoen could give me would be great, im not really sure what i should be looking at to change, im going to check the impeller like i said, change the coil, engine oil, thermostat, anything else i whould check????
thanks in advance to anyone who can help me out
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Overheating help!!!!!

there was some oil coming out of the valve covers so i am assuming that i am going to have to change those as well.
Howdy,


Can you expand a little on the "oil coming out of the valve covers"?

When you checked the oil after you shut it down, was it high, low, or right at FULL? (OR right where it was before you started it?)
 

Rumley

Petty Officer 2nd Class
Joined
Dec 5, 2009
Messages
105
Re: Overheating help!!!!!

the oil was right at full

the pressure seemed to be coming through at really high pressure along where the valve cover meets the block on top. im really bad at explaining things so im not sure if that made any sense to you.
 

fastimz

Petty Officer 3rd Class
Joined
Aug 11, 2004
Messages
85
Re: Overheating help!!!!!

How long after you went from wot to 3200 did it lose power? If immediately it may have flooded itself out then cleared up later and refired. The oil on the coil shouldn't cause an issue. If you ran wot for a time period you can push some oil residue out the valve cover breathers due to crankcase preasure. If yours are leaking around the gasket on the head, change them. Not causing your shut down issue. 175 shouldn't shut down the engine either. You should have the Thunderbolt IV system. Bad module, bad coil could be causes. Have you tried to run the motor since?
 

Rumley

Petty Officer 2nd Class
Joined
Dec 5, 2009
Messages
105
Re: Overheating help!!!!!

it was maybe 2-3 mins, i was letting my friend pass because i wasnt sure where he wanted to go for a ride, then i slowed it down a little bit more to cut into his wake. when i hit his wake it really lost power so i gave it more gas and it died on me. it does have the thunderbolt iv system.
after about 3 hours and the tow back my friend got me to crank it over to make sure it wasnt seized, and it fired up no problem, i didnt let it run because i didnt want to overheat again.

if any of this makes sense, what should i be checking for??
thanks for any help you can give me
 
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