1984 260 Mercrusier I/O.

[JoeRJGR]

All,

Last year my uncle gave me his 1984 CC Scorpion. Its powered by a 260 Mercrusier I/O. I ran it last season and it never got up to temperature, but otherwise ran fine. Long and short of it the thermostat was stuck open. Also, there was only about 3/4 of the copper sleeve left, the rest was gone. There was no gasket on top of the thermostat. I bought a new thermostat and copper sleeve, but the sleeve did not slip in easily. The housing was pitted, so I sanded it down until the sleeve would go in, but if I put the cork gasket on top of the thermostat and then the sleeve, the sleeve sits a tiny bit higher than the housing. I actually put the old thermostat in to check its height, but it sits the same way.

So my questions are, 1.

1. Is the cork gasket really necessary?
2. Is it suppose to sit a little higher and will the top of the housing push it down once bolted in place?
3. Do I need to clean up the inside of the housing so the sleeve sits a little lower?

Thanks for your help!

 

[muc]

1. MerCruiser seems to think so. So yes
2. Yes, I usually see 1/16” or so.
3. Sounds like you got it. I use a wire brush on a drill that is a little bit smaller in diameter to clean this area. But have sometimes used a flat screwdriver that’s been sharpened to scrape it down.

One of the places I see a problem is the bolt holes in the manifold. They get filled with rust and keep the bolts from screwing in far enough. Might want to check that or run a tap down them and blow them out.

 

[JoeRJGR]

Thanks for the reply, i was worried that the sleeve sitting up like that would cut into the top gasket. Good to know yours sits up a little bit too.

Thanks for your help!