Mercruiser 4.3MPI Dry Joint Exhaust Seawater Port

[msswany]

I have a 2007 Tahoe Q7I with the Mercruiser 4.3MPI, I am doing some engine work one it at the moment and where the water port is on the exhaust riser, there is also another port directly under that port that is plugged. I know the exhaust gasket has the restrictor facing forward so the small hole in the gasket is between the two ports. My question is, could I use the water port on the exhaust manifold vs, the port on the riser without any issues?

Thanks
Matt

 

[Don S]

Re: Mercruiser 4.3MPI Dry Joint Exhaust Seawater Port

Post a picture of the ports you are referring to.

Also need to know they serial number of your engine, and the type of drain system on your engine, along with if it's closed or raw water cooled.

 

[msswany]

Re: Mercruiser 4.3MPI Dry Joint Exhaust Seawater Port

Here is a picture of the exhaust manifold and riser. There is 3 ports, the middle one had the brass 3/4 to 1" barb fitting for the water to enter. Could I use either the top or bottom port?

Engine serial #OW689482

 

[Don S]

Re: Mercruiser 4.3MPI Dry Joint Exhaust Seawater Port

Could I use either the top or bottom port?

No, use the one that originally was used.
The top plug is never used for a fitting, always a plug.
Middle one is for the riser/elbow.
Lower one would be used if a full closed cooling system was used, the the middle one would be used too.

Don't try to reinvent the wheel, use the same ports for things.

 

[msswany]

Re: Mercruiser 4.3MPI Dry Joint Exhaust Seawater Port

I know its not the correct port, I am just wondering if changing them would actually affect the cooling in any way?

Thanks