Alpha 1 Gen 2 Possible Y pipe leak (Video included)

[Anthonyd516]

Recently replaced my transom assembly and I was careful to be sure to snug the y pipe on good but maybe I missed something. Anyway, the thing only leaks with the boat off and in the water Attached below is a video. Any ideas? Also, it leaks down both sides of the Y Pipe so I do not think its my shift bellows. I checked my bellows and they seem to be fine.

 

[harringtondav]

Your vid only had the sound of water trickle. No image.
When you say "Also, it leaks down both sides of the Y Pipe" are the rubber manifold couplings leaking? Also if you forgot, or pinched the Y pipe to transom plate seal you will get a leak low on the inside of the transom.

 

[Anthonyd516]

Your vid only had the sound of water trickle. No image.
When you say "Also, it leaks down both sides of the Y Pipe" are the rubber manifold couplings leaking? Also if you forgot, or pinched the Y pipe to transom plate seal you will get a leak low on the inside of the transom.

I just clicked on the video and i can see the footage. The water is streaming across the top of the center of the y pipe where it splits off to the two sides. Its hard to explain without you seeing the video. Heres a picture.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... I too, only get the sound,....

 

[harringtondav]

If the pipe didn't leak before your repair I think it's unlikely it was damaged during your repair. How old is it and your boat?
When the engine is running the exhaust blows most standing water out. With engine off the water level rises to the boat's waterline and the pipe fills above this joint.
Unfortunately any repair is going to take another engine pull. Then you can first check the torque on the transom joint. If it is loose, particularly on the top fasteners, water could be oozing out the top. The rubber seal in the transom plate doesn't set out much from the transom plate surface. It mashes flush with the joint when torqued up. If missing, or if you didn't replace the original it could leak.
Also the transom must be parallel inside on out. If it is not, the alignment with the exhaust manifolds could be off enough to put a downward force on the pipe joint.

 

[Anthonyd516]

If the pipe didn't leak before your repair I think it's unlikely it was damaged during your repair. How old is it and your boat?
When the engine is running the exhaust blows most standing water out. With engine off the water level rises to the boat's waterline and the pipe fills above this joint.
Unfortunately any repair is going to take another engine pull. Then you can first check the torque on the transom joint. If it is loose, particularly on the top fasteners, water could be oozing out the top. The rubber seal in the transom plate doesn't set out much from the transom plate surface. It mashes flush with the joint when torqued up. If missing, or if you didn't replace the original it could leak.
Also the transom must be parallel inside on out. If it is not, the alignment with the exhaust manifolds could be off enough to put a downward force on the pipe joint.

Its an 89, what do you mean when you say “the transom assembly must be parallel inside on out”

 

[harringtondav]

Its an 89, what do you mean when you say “the transom assembly must be parallel inside on out”

Merc's spec for transom thickness is round 2 1/16" to 2 1/4". ...don't quote me, but I think this is close. The tolerance on this dimension is very small. ....+- 1/16" IIRC. This means the transom plate and gimbal plate can be no more than 1/8" out of parallel. More than this and the alignment between the rear engine mounts, front engine mounts and gimbal bearing and coupler centerlines could be beyond adjustment with the front engine mounts.
My pal's transom was mush at the bottom of the keyhole cut out. This caused the rear engine mounts to sag, and took out a gimbal bearing.

 

[Anthonyd516]

I

Merc's spec for transom thickness is round 2 1/16" to 2 1/4". ...don't quote me, but I think this is close. The tolerance on this dimension is very small. ....+- 1/16" IIRC. This means the transom plate and gimbal plate can be no more than 1/8" out of parallel. More than this and the alignment between the rear engine mounts, front engine mounts and gimbal bearing and coupler centerlines could be beyond adjustment with the front engine mounts.
My pal's transom was mush at the bottom of the keyhole cut out. This caused the rear engine mounts to sag, and took out a gimbal bearing.

appreciate the knowledge however i aligned the engine with no trouble at all with an alignment tool. So i dont know if that makes any difference in what you are saying.

 

[harringtondav]

I

appreciate the knowledge however i aligned the engine with no trouble at all with an alignment tool. So i dont know if that makes any difference in what you are saying.

Then you're good. .. just brainstorming causes for any stress on the pipe.
Repairing the leak will be a pain to diagnose and fix. Not being cute here, but keep your bilge pump in good shape, and slip your boat on a lift or trailer as an alternative.