1990 evinrude 9.9 - question about cooling

[bktheking]

Hey all, it's been a while, yes i'm still alive and well and now messing with my own hunting motor. 1990 9.9 - we ran it last season without a hitch. This season, a week ago, we went out to setup for the hunt. Upon our return the motor smelled like it was burning- I put some water on the top of the block and it sizzled, yup it was overheating. Got it home and pulled the stat cover, it's a newer motor with the stat in the top of the head. They went cheap, some sort of bakelite housing with a swappable stat- no more metal. The "claw" as I call it that holds the mechanical portion of the stat and spring had broken. I could only find one piece of plastic claw so i'm assuming the smaller bits ended up in the water passage. We have since replaced the stat- the exhaust housing runs fairly cool to the touch on muffs, the water stream is good out the telltale and it gets fairly warm. My question is- the housing where the stat sits, is it supposed to get hot cause i can't hold my hand on it. I fear some part of the stat housing are lodged in the passages and restricting water flow. I know water is flowing to the stat cause we ran it briefly without the cover and stat, water came out the hole.


Thanks all!

 

[raczekp1]

the rest of broken piece tstat should be around the head or just at the water outflow chanel below head.
remowe the had, (resurface the head and new head gasket) and poke with wire at outflow hanel.
when the head is removed this hole is wisble.so just poke some long piece of wire

 

[oldboat1]

If the thermostat broke up, as I understand you, maybe other parts of the assembly did too. There is an "isolator" cap that goes over the spring. I have the same motor, but don't recall what it's made of -- thinking, though, that if it's not in place there might be heat transfer to the housing cover. I'm pretty sure the cover on mine is cooler than the top of the head, so what you are describing doesn't sound right to me.

If you don't want to pull the cyl. head cover, you could run it with the t.stat out (t.stat cover in place), and try to flush it out some. Check temp of the t.stat cover as well, if you flush like that. Alternatively, you can try flushing from the bottom up the water tube with a hose hook up (l.u. removed) -- can flush down from the t.stat opening as well.

The better approach is what raczekp1 suggests, though, as bits and pieces can lurk in water passages and cause later problems.