Chris Craft engine overheat

[chris_craft]

Hi - hoping that someone can maybe shed some light on a slight overheat problem on a 283 V8. One of the exhaust manifold 'logs' remained cool to the touch but the other side became so hot you couldn't touch it.
It is still raw water cooloing as I haven't been able to sort the heat exchanger yet. Took the manifolds off and ran water through but no sign of blockage or anything. Think it might have been an air lock but not sure - any ideas gratefully received!! Thanks dave

[rnb]

Sorry i am going back to basics. You took the manifold off and ran water through so you know its not blocked . Now with the boat connected up to water take off the hose that feeds to the manifold run the engine and check your getting a good supply. The pump sounds okay because its appears to be cooling one of the manifolds at least, im assuming there is only one pump.

[chriscraft]

Not sure if this is correct but I have a vague memory that the sherwood pump has 2 impellors mounted back to back, maybe the other impellor is jiggered also check you have not conected the pipes wrong way round so you get to pumps pushing against each other poss effect could be neutral flow, also I have seen a flow diagram somewhere on tinternet try search 283 plumbing and pump flow diagram

[Alacrity]

Also check where the water is injected into the exhaust (water injected bend?) to be sure that is not blocked up.

Good to hear from you Chriscraft, I was hoping you were going to be at Loch Lomond, we had a fabulous time up there in glorious weather.

Geoff

[se7en]

Early pumps have two bronze impellers, late pumps have two rubber impellers, which type is yours?

[Simonp]

And suggest check the raw water intake - where I guess there is some kind of grille to stop weed etc - mine got well corroded up and blocked on one occassion.

SimonP

[LaDauphine]

also check that there isn't a leak from the head gasket directly into the area so it is getting hotter where the gases are escaping.

having said that, not sure how you would do that other than compression testing all of the cylinders.

R

[chris_craft]

Thanks everyone. The 'logs' seem fairly clear and water running through. It is the bronze gear type pump. I think the head gasket idea may be a good one to follow up so am going to take the head off and have a look whilst it is stripped down anyway. The strainer seems clear. It splits into 2 pipes once inside the boat. The pump has two inlets and 2 outlets. I have the circulation diagram of the block and it seems to be working ok. Did read somewhere (after I had done it unfortunately) that you should not use a hose on the engine to flush it through as the pressure may effect the head gasket. Not sure if that true or not but it may be a possibility if it is! Really appreciate everyones input. Will still take it to the poole Quay on Friday evening and just loosely refit the 'logs' so she looks the part. Classic boats - you have to love 'em don't you!!

[chris_craft]

Hi guys. Pump checked and seems to be working ok. Cleared out the logs (loads of rust shale in there!) going to put it back together over the weekend and then see how she runs! Fingers crossed. If not will be atking it all apart again I am sure! dave

[chris_craft]

At last I seem to have solved the problem - one reconditioned impeller pump and she is good to go!! Tested the engine on Sunday and didn't miss a beat! Good water flow and nice cool engine. Thanks everyone!