yamaha 85 hp 1992 2 stroke overheat

And-Con

Petty Officer 2nd Class
Joined
Jul 18, 2009
Messages
146
I have a 1992 yamaha 2 stroke 85 hp engine that has been great for as long as we've had it, but lately i've had some issues with it. We just changed the thermostat(broken closed=bad) and the impellor(annual service) and it's still over heating. Unfortunately, it's kept at a location that we don't have access to fresh water, so the only time its been flushed is the odd time its been on a trailer. Recently I ran several batches of "salt away" through it in a last ditch cross your fingers and pray attempt to get on the water.

It will run on muffs with no problem, and it will idle all day, but the second the throttle goes up the temp does as well. The indicator stream is good and strong, and there appears to be a decent amount of water coming out the prop, so my suspicion is that some of the smaller passages are still plugged up with crud. However, I'm here to see ya'll's opinion since I assume it could be something else.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: yamaha 85 hp 1992 2 stroke overheat

if the thermostat,impellor and pump housing are known good the next step is removing the head and water cover jackets and scrape off the scale.
good luck with the bolts, remember if one breaks dont even think about easy outs.
 

And-Con

Petty Officer 2nd Class
Joined
Jul 18, 2009
Messages
146
Re: yamaha 85 hp 1992 2 stroke overheat

Well, i suppose that's what i expected to hear, but of course not what i wanted to hear. thanks for reconfirming what i suspected. on the bright side i think she's about to go somewhere with running water again soon.
 
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