NoQuarter

In going from a Corsa 50/50 exhaust setup to straight thru-hull, I understand you need to use a blocking plate on the transum. But, what about the outdrive? Do you have to switch to an outdrive without the exhaust bellow inlet?

Wally

iTrader: (1)

no...just the plate to keep the water from getting into the boat....the exhaust flows water through it normally when its running anyway so you dont have to worry about anything

pol98xc6

Im thinking about doing that to my system too. How do you go about blocking the exhaust that routs through the y pipe to the prop?

NoQuarter

Thanks Wally,

I don't think I asked my question correctly...

I understand that by leaving the outdrive exhaust bellow outlet open, that water won't come into the boat or get into the drive shaft/gears, etc... Moreover, while on plane the hole would be higher than the water, so water wouldn't come in. But, during climb out and coming off of plane water would enter the hole. Would this put lots of pressure on the drive? Could this possibly make it more difficult to get on plane?

What have others done that went from 50/50 exhaust to straight thru-hull?

Sorry for the length, and thanks!

NoQuarter

They make an exhaust blocking plate that fits a mercrusier transum plate. Not really sure, but I think you have to remove the transum and have it welded into place.

I'm sure someone else will chime in and know more.

JaayTeee

The block off plate bolts on to the area on the transom plate the y pipe connected to....no welding.

here's a picture:

http://www.mercruiserparts.com/Show_...=EXHUAST+PLATE

The engine has to be removed to get to the y pipe bolts.

If you have straight through hull exhaust, you can remove the
exhaust bellow on the transom assy . ( the bellow underneath the u-joint bellow)

You won't have any issues with planing or load on the drive.

pol98xc6

Is that the easiest way to block the bottom of the y pipe(taking the engine out)? Ive been thinking about it and I dont think its worth spending 1k for captains call if all I really want is 100% thru hull!

JaayTeee

I've seen people install plugs on each side of
the bellow atop the y pipe.

I've even seen some take a piece of an inner tube
and hose clamp it around the top of each side of the
y-pipe

ghittner

Just did this last year. There is a block off plate with 5, 12 pt. bolts that goes onto the hole where the Y pipe attached. Dealers and manufacturers add it for through hull exhaust when they remove the Y pipe. No gasket, just a good anaerobic sealant (Yamabond) between the plate and hole and you are good to go. There is no other modification that needs to be made. I did the opposite last year as I added Silent choice to my normal through hull. You may be able to get to it without the engine out but I doubt it very much. You want to make darn sure you get a good clean seal.
[email protected]. Greg.

Donzi502

ghitter is on the money.