1995 Johnson J25REOR dosen't throttle up

[bottomfish]

I have a 1995 Johnson J25REOR that coughs and stalls after idling for some time and doesn't throttle up. It will restart no problem. I replaced the power pack last year due to the same issue. I did disconnect the temperature sensor and was able to throttle up and get on plane. The water out of the exhaust relief seems pretty hot. The water out of the hose is cool. I'm thinking there is a clog somewhere causing overheating. I want to replace the thermostat but reluctant to take the cover off due to age of the bolts. Any recommendations on how to flush the engine or diagnose a power pack? Thanks!

 

[Bosunsmate]

Put your hand on the head, how long does it take to get hot?
It might be a stuck open thermostat or a poppet valve (is that engine has one)

 

[Bosunsmate]

By the way it shouldnt get so hot that you cant keep your hand on it

 

[bottomfish]

Unable to keep my hand on it.This could be a can of worms taking the cylinder head cover off to replace the thermostat. Any suggestions on how to flush out and engine before I attempt that?

 

[Bosunsmate]

Ive never flushed an engine out, i just take the head off and clean all that then i put it back together. If you do end up taking the head/cover off then just undo the bolt a bit and then retighten a bit, as if you continually loosen it the gunk will get stuck in the threads making the bolt harder to turn and it will then seize hard and thats when the head comes off the bolt.

To flush i suppose you could drop the leg and attach a hose to the intake pipe and squirt water up there, but not too hard otherwise you risk blowing out some seals etc

 

[juno pierrat]

On my older motor i found that getting to the bottom head cover bolts out was a pain, but when that didn't solve the problem the head needed to be removed and those bolts could be reached much easier, now that you pretty sure its over heated a new head gasket, thermostat, and cooling passage cleaning might be the way to go,