Exhaust Blocking Plate question
 

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?

Re: Exhaust Blocking Plate question
 

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

Re: Exhaust Blocking Plate question
 

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?

Re: Exhaust Blocking Plate question
 

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!

Re: Exhaust Blocking Plate question
 

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.

Re: Exhaust Blocking Plate question
 

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.

Re: Exhaust Blocking Plate question
 

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!

Re: Exhaust Blocking Plate question
 

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:rolleyes:

Re: Exhaust Blocking Plate question
 

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.

Re: Exhaust Blocking Plate question
 

ghitter is on the money.

Re: Exhaust Blocking Plate question
 

where can I get the block off plate?

Re: Exhaust Blocking Plate question
 

If you dont want to yank the engine cause yo cant get at the bolt or dont have the room otherwise...just go to home depot and get the rubber plumbing caps they make and cap off the top of the Y-pipe and leave it all in place....nothings gonna get hurt and you can always hook everything back up later if you decide to sell or get harrased by the water cops for being too loud....

Re: Exhaust Blocking Plate question
 

Re: Exhaust Blocking Plate question
 

Any dealer or good boat shop can get it for you. If you run into a HUGE problem, I have one and you can replace it for me sometime in the future OK? [email protected]

Re: Exhaust Blocking Plate question
 

I have a plate i was going to use on my project boat but am leaning towards going back to the Y-pipe setup.....i'd be willing to maybe do a trade for a y-pipe if anyones interested :)

Re: Exhaust Blocking Plate question
 

thanks ghittner I will talk to my boat mechanic and see what we are going to do!

Re: Exhaust Blocking Plate question
 

Years ago a good prop man told me to remove the bellows on the outside of the transome assy so there wasnt a problem with suction with the prop. As I understood it, and I may be wrong, been a long time and he has sinced past away. The open hub on the prop will have a suction, or low psi area, caused by the prop going thru the water. If the rubber bellows that meets with the drive when in the down position, is not removed there was an ill effect. Removing it allowed air to enter the prop area and stop the ill effect (which I cant remember what it was). I have been running without the rubber hose (not really a bellows, if I remember correctly) for 15yrs or so.. two boats. No problems..
Hope this helps.

D*i*c*k

Re: Exhaust Blocking Plate question
 

I heard this as well years ago. Let air into the system to prevent a vacuum forming behind the prop. No idea if there is any truth to it but it makes sense.