Over heating 350ci???

[Gappy]

Howdy, New guy here.
I have '87 Century 3000 w/ a 350 IO, Alpha I, 20ft boat. I am having a over heating problem. So I pulled it out of the water and submerge the lower unit in a tank of water and run it. My boat exhaust throught the bottom of transom. There is water very intermittently coming out. A whole more "not" than "is". I have a shop manual and I believe the boat has a impeller as well as the water pump. The water pump is not leaking and the belts are all new and snug. Am I safe to assume that the impeller is the problem? If so, what is a good on-line source for parts?
Thanks for the help!!

Tom

 

[cooter2506]

Re: Over heating 350ci???

Sounds to me like an impeller problem. Has yours ever been changed? Where to buy them is at iboats. I would get the everything for the impeller you can . Lower housing and all.

 

[crazyinkc]

Re: Over heating 350ci???

Yes!

 

[erikgreen]

Re: Over heating 350ci???

We're all new guys at some time or other, welcome to iboats

Water coming out the bottom of the transom (actually the bottom of the sterndrive's bell housing) is normal at low rpms... I asked the exact same question when I signed up here. At the bottom of the transom are relief holes that let water and exhaust out if there's not really enough pressure in the exhaust to push out the prop hub consistently.

If you've never replaced the impeller, it would be good to do so. You can't assume that's the cause of the overheating though. Others will chime in, but it could also be a restriction in the manifolds, problem with the main circulating pump, etc.

You can buy the parts you need right here at iboats, or at your local boat shop, or a lot of other places.

Erik

 

[Gappy]

Re: Over heating 350ci???

When there was no water coming out of the transom, it was at idle. I don't know if the boat has the original impeller or not. I bought it last year from the original owner and it only has 300 hr. on it.

 

[cooter2506]

Re: Over heating 350ci???

IMpeller should be changed every year for good measure. I beleive you can get two or three years out of it but for the price of them I plan on changing mine every year just for the piece of mind. Even at idle you should have water coming out the lower part of gimble ring.