Exhaust Manifold Leak

[h205150]

I have a 1987 OMC 4.3 that I just did a rebuild on, the engine is back in the boat everything is working fine except I cannot get the left exhuast manifod to seal it leaks water when running I have bought second gasket for this manifold installed still leaks, also have tried hi temp silcone RTV and a gasket no luck the leak is between the # 3 and # 5 cylinder exhaust ports.

 

[wire2]

Re: Exhaust Manifold Leak

It may be distorted. Take it off and lay it on a counter top. Can you slide a strip of paper under #3 flange?
Are the block mating surfaces clean & smooth?

 

[Haut Medoc]

Re: Exhaust Manifold Leak

It should not leak water anywhere near the exhaust ports.....
Possibly where the manifold meets the riser......
It sounds to me like you need new manifolds/risers.....​

 

[Don S]

Re: Exhaust Manifold Leak

If this is the one piece manifold/riser combination and water is leaking out externally, then they are dead and need replaced. They are 20 years old.

 

[h205150]

Re: Exhaust Manifold Leak

Thanks a bunch for the input, I guess it is off to a search engine or Iboats to see if I can find some Manifolds

 

[h205150]

Re: Exhaust Manifold Leak

Hello all, well I slept on this problem and got up this morning and pulled the Manifold off for the 4th time and found the culprit to my proplem the shop I took the engine to failed to put the plug on the head, hence the reason why there was a flow of water beween 3 and 5 exhaust ports. After going to the rebuild shop voice a little frustration they gladly gave me the plug with a new gasket. a little quality assurance on my part and theres would have gone along way on this problem. Thanks so much for all the input.