water leaking at bottom of inner transom plate

[lime4x4]

Working on a 1986 alpha sterndrive.With a260 mercruiser v8 Over the winter i replaced the transom and outer transom plate. I replaced all the bellows and seals. When sitting in the water i have a slight trickle of water leaking at the bottom of the transom inner plater. Looked like it was coming either from the exhaust y-pipe or where the trim hoses come thru. I filled the bilge up with water no leaks evident on the outside. I've ran the engine for a good 45 minutes at 1500 rpm,s on muffs and the bilge stays bone dry. Is possible to still have a leak in the exhaust somewhere that will only show up when it's in the water do to outside water pressure? I beleive it's exhaust cause when i pull the boat out after a 15 minute run the water is rather warm

 

[xltier]

Re: water leaking at bottom of inner transom plate

Working on a 1986 alpha sterndrive. Over the winter i replaced the transom and outer transom plate. I replaced all the bellows and seals. When sitting in the water i have a slight trickle of water leaking at the bottom of the transom inner plater. Looked like it was coming either from the exhaust y-pipe or where the trim hoses come thru. I filled the bilge up with water no leaks evident on the outside. I've ran the engine for a good 45 minutes at 1500 rpm,s on muffs and the bilge stays bone dry. Is possible to still have a leak in the exhaust somewhere that will only show up when it's in the water do to outside water pressure? I beleive it's exhaust cause when i pull the boat out after a 15 minute run the water is rather warm

check your shift cable bellows real well.had one that caught going on by the ujoint bellows and rolled under.

 

[Don S]

Re: water leaking at bottom of inner transom plate

When you replace the transom shield, did you put a new seal on it?

 

[lime4x4]

Re: water leaking at bottom of inner transom plate

yes i used a new outer seal

 

[lime4x4]

Re: water leaking at bottom of inner transom plate

I also used a new y-pipe to transom seal

 

[Don S]

Re: water leaking at bottom of inner transom plate

Many times I have remove the engine, reinstalled the drive, capped of the exhaust tube/s and put the boat in the water strapped to the trailer so I could find the leaks.
It's amazing how much you can see once you get the engine out of the way.

 

[Big Boat Bay Buster]

Re: water leaking at bottom of inner transom plate

I have the same engine/drive set-up with the same problem. On the muffs it was fine. At the dock, running at idle it was fine. Get out in the open bay and the leak would start dripping below the y pipe. I have it all apart and will be putting it back together tomorrow with a new main seal, new o ring for the y pipe and a new gasket for the hydraulic block. I did a good inspection and nothing jumped out at me as being the problem so I'm hopeing for the best.
Pay special attention to the 2 bottom bolts on the transom plates also. The ones with the zincs on them.They can corrode and have a rubber seal on them which I'm sure can go bad. You can get replacements, but they are about $45
Was your transom solid and dry? Try changing the hydraulic mainifold block gasket-its real cheap. ebasicpower.com has them GLM32500 $1.09
If I find anything worth reporting tomorrow, I'll post it.
Chris

 

[lime4x4]

Re: water leaking at bottom of inner transom plate

I replaced the wood in the transom. used all new seals and bolts. That is my next step is to pull the engine out and reinstall the drive. And let her sit on the trailer at the boat ramp and c what happens

 

[Bondo]

Re: water leaking at bottom of inner transom plate

Ayuh,.... Man, That Sucks....