Need help Leaking boat

[edgewater1]

My boat leaks in the back left side, where the gas tank and ski locker under it, i can see own with a flash light and there is water all around the exhaust pipe.
I dont know were it is leaking from? has anyone had a similar problem, is it the exhaust pipe or the swim platform mounting brackets?
my boat 1991 sunsport

[csuggs]

It could be either. Most often it is the exhaust, especially if you have the original Supertrapps. The word is that the Supertrapp exhaust is what caused A LOT of the older Supras to leak - resulting in rotten stringers. Better check it out carefully.

[edgewater1]

how do i fix that?, i dont believe i have supra traps though

[stinky_1]

unscrew the exhaust covers, pull them out as much as you can or until you are able to get silicon in behind them. Load it with silicon all the way around and put them back on.

[wotan2525]

Yes. Take the exhaust off as best you can and use either RTV or 3M 4200 to seal them. Do the same with your swim platform bolts (don't totally remove them, just loosen enough to apply sealant to the threads.)

It's an old boat. It will probably always leak. Try to cut down on the places that are the worst and install an automatic bilge pump. Problem solved.

[oward1202]

My 85 comp is the same way. I already have a auto bilge so I wasn't too worried about finding the leak. I couldn't find it all summer last year until I started taking off the supra traps just to see how they worked. As soon as I got them off, water began to drip from behind the plate that mounts on the fiberglass. I guess I just found it by accident. I am going to pull off the plate completely, fill the holes, rotate the plate slightly and start new holes. The existing screws don't have much of a bite on them. I figured this should fix it. Also be sure and check your speedometer mounts. Good luck!

[edgewater1]

thanks i'm going to pour the 4200 on, and a new bilge pump in the spring, and recommendations?

[oldman]

Edgewater
Do you think the leak is from the through hull fitting? Or could you just have a leak in you exhaust line?

[edgewater1]

i know i have located it to the part of the boat where the left exhaust line comes in so that was my first thought a through hull problem but i'm open to ideas and things to check. I bought the boat as a donation and do not know the history all though i do kinda of know the previous owner(A friend of a friend i met at a party a few year back, i know i know but he gave his e-mail and said he had stuff he could give me for the boat that he did not donate)

[oldman]

I was just thinking it might be good to check exhaust line. If you could seal your exhaust at exterior transom with a internal plug or fernco hose clamp cap. Something from your hardware plumbing store. Then remove hose clamp at exhaust manifold riser, that should be a higher point than rest of exhaust line. Fill with water. You could even put a low psi air presser test on line with some plumb fittings and gauge. My exhaust lines leaked because of bad mufflers and loose hose clamps. Over the years your exhaust system can break down, because of heat and age. At some point I think it's a good idea to update all to new, if yours is original.

[Okie Boarder]

If you run the engine in the driveway on a hose do you get water in there or only when you're on the water? That might help narrow it down between the two.

[edgewater1]

only in the water

[OUI]

Although 4200 is less permanent then 5200, I'd use some other type of silicone or bedding compound. You may want to take them off sometime in the future and if you use 4200 you may not be able to.

[wotan2525]

Although 4200 is less permanent then 5200, I'd use some other type of silicone or bedding compound. You may want to take them off sometime in the future and if you use 4200 you may not be able to.

I used black RTV for this very reason, though others on the board disagreed.

[Salty87]

don't forget to seal the joint where exhaust pipe meets supra trapp. it's up the pipe about 2-3".