mercruiser 120 i/o random stall and skip

by mike
(webster, ny)

i have an 83 mercruiser 120 i/o that will start up and run mint for about an hour or more after trolling then motor will quit and sometimes start up hard also at this time it will devlope a random skip mabe once every 5 or seven minuts then after i take off to a WOT it will run all bogged down. i have installed new plugs, new cap, new rotor, rebuilt the carb, installed a water sep/filter, all new fuel lines, new plug wires, new condenser, and ran a can of sea foam thru it all. I think my boat hates me! Any thoughts???