The Cape Cod Crusader

[Blue_Heron]

Originally Posted by FishStretcher

I will need education on this one. If there is a good website for how this works, or you want to type it out, I would really appreciate it.

I dragged my installation manual out of the shop to check the requirements. The manual is for Mercruiser gasoline sterndrive models and includes the 350 Mag MPI in both Alpha and Bravo configurations with Serial number OM668000 and above. Do yourself a favor and throw out that Seloc manual and get the factory service manual. You'll need two manuals, one for engine, one for Bravo drive.

Anyway, the installation manual says the minimum exhaust elbow height is 13" (33.0 cm) above the static waterline with the boat fully loaded. That means full tankage, gear and crew. My fully loaded static waterline is around the middle of the scuppers unless everyone moves to the back of the boat. That puts it an inch or two below the deck. Which would make minimum elbow height around 11 or 12 inches above the deck to the top surface of the elbow casting. I just checked mine and it's at 11 3/4".

If you increase your exhaust elbow height, in addition to the riser extensions, you'll need longer intermediate elbows. Those are the ones that connect the riser elbow to the Y pipe. They will have a slightly sharper angle than the shorter ones.

Something else you might want to check:

From page 19 of the installation manual - IMPORTANT: Bravo closed cooled models require a through the hull or through the transom pickup in addition to the sterndrive water inlets in order to meet the minimum flow specifications.

So there should be a Y fitting on the engine cooling hose behind the seawater pump on the starbord side of the engine. The Y fitting should have one hose fed from the Bravo transom assembly, and another fed from a through hull.

Dave