leaking exhaust Manifold

I have a 81 Nautique, has a pin hole leak in one of the exhaust manifolds. Is it very hard to change? Afraid the bolts will break and have to redrill holes in the heads. Can it be patched with anything? so we can get the rest of the summer to use the boat.

David, was it you that posted an earlier fix for cracked manifolds? Someone (maybe you?) had the great idea to drill a series of holes along a crack, sized to tap threads into, screw a screw into the hole, gind off the head, and drill and tap a hole right next to the screw that you just inserted. Repeat until the whole crack is filled. I think they said to begin by drilling a hole at each end of the crack so the crack will not spread.

Now if the problem is a leaky gasket - that's another story altogether.

As far as frozen bolts go, if you are real good with an acetylene torch you can expand a bolt by turning the head cherry red with a lot of heat so as to do it quickly and minimize heat transfer into surronding parts, have a water squirter ready so as soon as you remove the torch squirt a lot of water on the cherry red bolt head to cool it quickly, before the surrounding parts have a chance to cool. I usually pour water on the bolt head until it almost stops giving off steam.

Immediatly follow the water squirt with your wrench. If the part is on your bench you can pour water from a can or bottle instead of squirting it. The idea is to cool the bolt quickly and not the surrounding area. Try not to let the water run onto the area surrounding the bolt. If done properly the bolt will easily unscrew. If you find it does not unscrew walk away from it unti it completly cools down and try again with more heat and more water. I have used this technique a lot over the last 40 years. Don't set your boat on fire. Flaming plastic is hard to extinguish.

hey buddy if its just a crack or pin hole and you dont wanna take out the manifold grind it down with a air tool with a metal grinding bit and then get some quick steal from a parts store and mix up some in your finger tip then press in where you grinded the hole and wait for it to dry 30 minutes and have fun you can sand it down a bit and paint to match manifolds this is what i done so i wouldnt have to buy new ones this year works great put 30 hours on it so far and no problems hope it helps

Just wanted to update, I took the advice of using Quick steel as temporary fix of my leaking exhaust manifold on my 81 SN. Put some over the hole and it has worked fine now for the whole summer. Will try to change the manifold this winter. I tried some other products but they all burnt up and the hole was still there. Quick steel works great!