Overheated engine

[dantheman]

My boat neighber (who's not into computers or internet) has 1981, closed cooled, 270 crusder engines. The other day, the stbd engine overheated, he let her cool down, then started it, it ran good but there was no water coming out of the exhaust, so today he replaces the impeller and water comes out even better than the port engine now. He takes it out and it's runing great, pumping lots of water, then suddenly it overheats (at 10mph) and he turns it off. Comes back and the entire left exhaust manifold on the stbd engine had turned from light blue color (the regular paint) to almost black, and the big rubber hose that connects the exhaust manifold to the muffler got almost melted. My guess is the exhuast manifold is bad. So the question I have is, if we pull the exhaust manifold off, what is the trick to not breaking off the bolts? or does it really sound like the manifold is bad and not something else. The other manifold that gets water from the same T in the cooling is fine. any help would be great. Thanks, Dan

 

[Kay Lee]

Sounds like there's a blockage in the water flow to that manifold.

Larry

 

[Jimmy Buoy]

Perhaps, vanes off the old impeller?

 

[dantheman]

he found all five vanes that came off the impeller, but I do think it's some kind of blockage.. any idea's on how to best get the bolts off the manifold in case we have too? with a hot engine maybe? or cold.. Thanks, Dan (LT. Dan)