I just purchased my boat and am having problems. The sea trial went fine, but now the engine is giving me problems.<br /><br />It will run fine at high RPM (4,500 to 5,500), but anything between 1,500 and 4,500 it will give me problems responding (start sputtering and shaking) and will die.... It sounds as if not enough gas is getting to the engine. Sometimes at idle it will just suddenly die as well... I checked the fuel/water seperator and nothing found... the engine was just tuned up with all spark plugs being replaced, fuel filter, and fuel/water seperator.<br /><br />HELP PLEASE.....