Need Help 350 chev water in pots checked everything

steve966

Recruit
Joined
Oct 20, 2013
Messages
1
Hey everyone need some help from some guys that have been through a few older ski boats. to cut a long story short got water in both back pots in brand new 350 only done 22 hours, which i thought was strange to do both sides but took it home compression checked it all were perfect, so i pulled exhaust manifolds off and inlet manifold pressure tested them no leaks, so put it all back together new gaskets checking everthing as i went hooked it up to the water at home and fired it up did the timing running like a dream turned it off an on a few times all good, took it to the river did a couple wakeboard runs then turned it off in the middle to swap boards went to start it agein an hydrolock pot 1 and 2 only, pulled plugs out turned it over empty it out and started it agein running perfect HELP ....
 

NHGuy

Captain
Joined
May 21, 2009
Messages
3,631
Re: Need Help 350 chev water in pots checked everything

Welcome to the forum.

So this is a ski boat with the motor facing backward right? It sure sounds like cooling water is in the exhaust and it's getting in your cyls when shut down.
Both sides does seem weird to me. how does the exhaust plumbing run, 2 into one and out? Or full dual?
You can test the risers too, and you need to make sure there's no water tracks on the gaskets between the risers and manifolds. They have to really seal so no water can get in there. On my sterndrive there are a couple types of gasket material available. I get the silver colored oe ones, they have graphite coatings on both sides which really makes the best seal. When I was new at this I made the mistake of reusing them, doesn't work. They are one time gaskets. Maybe it's that, I hope so. It's a cheap fix.
Here's a link to a process to test your stuff, it's from the stickies at the top of the forum. http://forums.iboats.com/mercruiser...s/testing-exhaust-manifolds-leaks-288629.html

You gotta go through that stuff, it's gold for DIY folks.

If I am wrong someone who knows more will say so, but it wouldn't surprise me if it's the water jacket exhaust. If the motor is that good it almost has to be.
 
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