Testing Y pipe for leaks- no outdrive installed

[bashr52]

I'm getting ready to get my boat out of winter storage this weekend, and before I put the drive back on, I want to verify the flaps are still in the exhaust, and check the Y-pipe for leaks. I was having an issue last season with water leaking into the bilge, and I want to verify if the Y-pipe is leaking or not, and may be the source of the water. I will be replacing the bellows, gimbal bearing, shift cable, etc at the same time. Should I plug the end of the pipe somehow to see what happens when the water sits in the pipe, vs just running through?

 

[Brentathon]

What type of drive?
Don't discount the upper swivel shaft seal....usually is a small trickle, that works its way down to the look like it's coming from the bottom of the Y-pipe....especially if your drive sits low in the water (i.e. stern heavy boats). JR Marine makes a 17-4PH (stainless) swivel shaft, which is awesome.

 

[Scott Danforth]

if you have a leak, it will be where the flaps fell down and the shaft wore thru the y-pipe. you should see the hole.

you can try to fill the y-pipe and look for leaks

then again, with the motor out you should be able to see the flaps

 

[bashr52]

Alpha 1 gen 2. Engine is in, drive is just off for a reseal and bellows/gimbal bearing change. I could hear water trickling into the bilge after I pumped it out, never could see it which leads me to believe it's down low under the engine, in the area of the Y pipe

 

[Bt Doctur]

If you didnt fine water in the main bellow you can eliminate that part , next is shift cable bellow, easy enough to pull and see cracks or tears.
Y pipe ,you should be able to spray into the exaust and see it drip inside the boat, that would be a bad Y pipe

 

[bashr52]

I did find water and gear oil in the drive bellows when I pulled it. The driveshaft seal on the outdrive was bad and leaking gear fluid, which is why I pulled it before storage. Perfect opportunity to change the water pump too! I have a new shift cable bellow as well which will go in, but I just bought the boat late last season so pulling the exhaust to check the flaps and pipe at the same time.

 

[Bt Doctur]

Then I would go with a main bellow leak or the mounting gasket was damaged or the thick rubber ring was not glued in place and was dislodged