I believe its not running on all the cylinders. I bought the boat recently and it had been sitting for 10+ years. First two carbs I took off looked like brand new on the inside so I didnt bother with the rest. When checking for spark it had spark on all 6. I can get it to run, and idle, and in neutral if you rev it up a little bit it will take off and hit on all 6, and really smoke bad, but it gear you can't get it past 1500 rpm. When its running and its in gear and you give it gas it will get boggy, but will occstionally spit out a cloud of smoke. Whats wierd is when I have taken the plugs out after running it to check them all are completely sopping wet with gas. Im stumped. Its got good compression, spark, and fuel... what more can it ask for?