Bought a USED boat last year. Seller said the engine ran great. It did when we fired it up hooked to a water hose. No sign it was down on power. Ran a compression check later and found one cylinder DEAD on compression. 120 hp V4. Three cylinders had 110-115 PSI and one @ 0 psi. Traded for a 140 with less than 200 hours. Took to a marine mechanic (bought engine from) and he installed it. Had him do some other work including pulling and cleaning the two gas tanks. Took it out and it fell right on its face upon popping the throttle to it. Ran a fantastic 8 mph (GPS speed). Gas was filthy and fouled the carbs. Took it back and told him to do it again at no charge as I'd paid once. He did so at my "persuading". Runs great now after changing out the primer bulb due to the alchohol eating the original up inside. Going out this weekend again.