When I first started the engine this Spring (April) it idled OK, but ran rough above about 2000 RPM. WOT = 4400 RPM at 19MPH. I ran the boat on the lake at various speeds for about 20 minutes in hopes that the problem would go away. It did not. I replaced the engine's inline fuel filter, checked the fuel pump filter screen, and put in fresh gasoline, all to no avail.<br /><br />Last Fall, I ran all of the gas out of the engine and sprayed oil mist into the cylinders to winterize it. At that time the engine ran normally with WOT about 5500 RPM at 23MPH. <br />My 1993 Force 90 HP outboard is mounted on a 24' Crest Pontoon boat. When I bought the boat in May of 1999, the power head was completely rebuilt. This included new pistons, rings, bearings, gaskets, and seals. All three carbs and the fuel pump were rebuilt. Thermostat and spark plugs were replaced. Last year the water pump impeller was replaced. No other work has been done on the engine since that time. <br /><br />Any suggestions ?
