i am not a boat mechanic, but, does the motor just not seem to power up as quick now and has your top end speed changed from new. any changes to the jack plate or prop? proper maintence such as fuel filter change spark plugs, also some of the gasoline now has a tendancy to break down the inner lining of older fuel line hoses. disconnect at your primer bulb and inspect the fuel line for stuff that looks like (chipped off clear coat) as best i can describe it. this was a major issue that has been seen the past two years. if those are not the problem, i would post on bbc in the evinrude section. but a quick way to tell if its a fuel line issue is to get the correct inside diameter hole fuel line (about 5 ft) from autozone ect. and take a 5 gallon plastic gas can and a friend to the lake. take the motor cover off and connect one end of the new hose to the fuel housing have a friend hold the other end in the gas can, let it idle for afew minutes to clear and warm then see if the hole shot changes. if it does then i would change out all my fuel line and filter. hope this helps.