class6

All gaskets were Merc. Fuel is 91 non ethanol. Engine tune, just the limiter bumped to 5400. Motor checks out great. Runs as it should. I do run mufflers though.

Knot 4 Me

Crazy!

BUP

iTrader: (9)

I remembered that I have seen somewhat the same from a smallblock with thru the prop exhaust and his problem was a water shutter / aka flapper valve was lodged down in the Y pipe, that caused a exhaust restriction. this restriction added exhaust heat and like I said before - exhaust gases can be corrosive.

for your app in the pic -------------

Maybe possible an exhaust problem of some sort - back pressure or restricted exhaust flow from the mufflers installed - IMO this could be a good guess here and possible a fuel additive used ??

class6

No additives unless the marinas are putting them in.

Drock78

iTrader: (2)

Running 91 non-ethanol would cause it to run rich

Keith Atlanta

Ever touch the fuel regulator?

I burned up pistons and never melted the turbulators. Thats nuts!