over heating an engine cause the manifolds to crack?
 

I have just bought this boat and when I recieved it the raw water pump was bad and not pumping at all. I am wondering if someone ran it hot if it would crack the exhaust manifolds. I am asking because I can not find the reason I am getting a lot of water in the manifolds.

Gasket between manifold and riser bad?

What kind of manifolds are they? It seems a little unlikely to me however not real certain. Is that the only thing you have noticed wrong at this point? I have not run into this before however like the other post mentioned in regards to the riser gasket being burned out. I suppose that's possible from excessive heat.

I pulled off all 4 risers cleaned very well, saw on signs of roting, surfaces cleaned up easily, old gaskests did not seem to show sign of leakage. I installed new gaskets used permantex head gasket sealer ( the brown stuff) let it sit overnite to dry. Put fresh oil in today and ran it on hose for about 15 mins changed oil, it was like coffee colored with a lot of cream in it. And they are glm manifolds which look to have not much use to them. I have been looking for a professional to pressure test them with no results.

Head Gasket? Intake manifold gasket? Cracked oil cooler (although this will more likely result in oil in the water due to the higher pressure of the oil system)

Do they dump into rubber hoses and how long are the hoses?

If it over heated you could have warped heads. Seen it several times in auto engines.

i installed thesea pump hoses backwards one time and over heated the motors and I did crack an exhaust manifold. :eek::grinser010:
I had a crack about 1/2 inch long. cap off one of your ends and fill the other end with water you will see very soon if they are leaking. good luck.:evilb:

it can happen....my guess is that they are rusted thru somewhere, common on older manifolds....the 1990 boat ?

It is also possible the dry exhaust coming out damaged the inner liner of the rubber exhaust hoses. I have seen this happen and the liner dropped down and caused the engine to revert water. Look and/or feel around for any bubbles or splits in that inner hose.