exhaust manifold block off

[brplut40]

I have a 1993 Sea Ray with a 4.3L Mercuiser. It has a Seakamp FWC system that moves coolant through everything except the exhaust elbow. I have been having problems with the exhaust manifold block off gasket. When I first bought the boat the gasket had failed and a cylinder filled with coolant. We tore it down, and replaced the gasket, but when we did there was a very slim metal plate in addition to the gasket. Now there is only a gasket. The dealer stated that the gasket superseded the old plate and gasket. The new gasket number is 27-8637251. Does anyone know if there still should be a thin metal plate and a gasket. It really sucks that these gasket keep failing, but i can understand that gaskets alone were not made to take 12-15psi of pressure from the cooling system constantly.

 

[Don S]

Re: exhaust manifold block off

Do you have the actual Mercruiser 27-8637251 gasket, or an aftermarket substitute for that number.
The OEM gasket has a thin metal plate made inside the block off gasket.

 

[FreeBeeTony]

Re: exhaust manifold block off

I used the same gasket (OEM Mercruiser) and have not had a problem.

Gotta make sure it's Mercruiser.

 

[brplut40]

Re: exhaust manifold block off

I have the quicksilver, which I think is Mercruiser's brand, gasket. Last time we put it together we did not use any red RTV so we will try that this time. Hopefully it works better this time.

FreeBeeTony do you have any advice when I put it back together to make sure it works?