Going to take a gamble

[duckmnn]

So I developed a exhaust pop through carb at 3300-3500rpms. I back off throttle clears up. First thing came to mind was I crapped a flapper valve . May been lodged in exhaust . After tearing into . I have water puddling front of #5 cylinder in exhaust manifold. I changed riser spacer block and both gaskets no help. So Bought manifold hope it’s that and not cracked water jacket in head . Has anybody else delt with cracked exhaust manifold ?

 

[Espos4]

Yes. Corrosion builds up inside the manifold water jacket. It doesn’t drain properly for winterization, therefore antifreeze doesn’t get to it. Add in a cold winter and you get a cracked manifold.

I assume you are in fresh water where they last a long time, but 24 years may be enough to do it.

 

[duckmnn]

Yes. Corrosion builds up inside the manifold water jacket. It doesn’t drain properly for winterization, therefore antifreeze doesn’t get to it. Add in a cold winter and you get a cracked manifold.

I assume you are in fresh water where they last a long time, but 24 years may be enough to do it.

I installed new riser and Barr manifold 6 years ago . I’m hoping it was flaw in the casting . And a new one corrects problem