I have a 120 mercruiser that pops out of the carb @ WOT. I know for a fact I have a lot of junk in my gas tank due to the fact I have to clean out my filter quite often. I tuned it up last year. Replaced everything but the coil. I have a new one, but haven't had time to install it yet. I'm going to rebuild the carb and replace the fuel tank at the end of this season. I'm betting on it being in the fuel system somewhere. Haven't had a chance to check the fuel pumps ability to supply the carb yet either. Any suggestions before I dig into this thing. Oh, it runs about 4000rpms @WOT, which is within the range it should.
