Dripping exhaust manifold

Well 3rd post this week trying to get this boat into shape! I changed the impeller yesterday on my new to me 1987 SN 2001 with 351W. When I fired up my boat, just for a few seconds without water hookup, I noticed that it was dripping from the bottom of the exhaust manifold. Then I noticed that there is some kind of JB weld or something on the bottom of the manifold. The leak was slow, just dripping. The other side of the engine does not have any kind of sealant on it but it also was dripping from the manifold. I guess it has a crack in it too.

Does anybody know of something like JB weld that is made for repairing these? Is a small drip that big of a deal?   Thanks!

Cy

mine leak a little as well. exterior leaks aren't that big of a deal...the water is leaving the exhaust some way or another. However, manifolds that have cracks are more likely to develop cracks in the interior jacket which would be a very bad thing (water gets into the engine).

I repaired mine with some JB weld as well that helped for about a month. I ended up keeping my eye out for boats that were being parted out and nabbed a pair. I then took them to a machine shop to have tested and resurfaced. I haven't noticed a change in boat performance or temps between the cracked manifolds and the non-cracked ones.

Thanks for the help fellas,

If I have an internal leak then it would be getting into the oil right? I changed the oil 2 days ago. I drained about 4 quarts and it did not appear to have any water in it.

TurboZinke wrote: When I fired up my boat, just for a few seconds without water hookup, I noticed that it was dripping from the bottom of the exhaust manifold. Then I noticed that there is some kind of JB weld or something on the bottom of the manifold. The leak was slow, just dripping. The other side of the engine does not have any kind of sealant on it but it also was dripping from the manifold. I guess it has a crack in it too.

Sounds to me like you're dripping water after a few seconds of running the engine dry.
Why don't you hook up the water and run it to see what you have for leakage, It'll probably be different

Then after you run it for a while, you can check the oil and pull the spark plugs see if they're wet with water and turn it over with the starter and see if any water comes out of any cylinders. And, yes you can have water in the cylinders from internal leaks in the exhaust manifolds without getting it in the oil

Any way you look at it you're rolling the dice. It's your call

Gary S wrote: +1 Here's an idea- Just go get new ones,they are still available. Some day they might not be,PCM does not seem to care about other Ford parts they made to convert them to marine use

+1 or at least start saving for them. Your NEW pair should last you the rest of the boat's life as long as you don't run in salt and properly winterize.