1. Do your annual maintenance. Whether you work on your boat and engine(s) yourself, or take them to your dealer or service shop, make sure your maintenance is up to date. The manufacturer's recommendation to service the engine at "100 hours or annually" actually means whichever comes first, points out Capt. Kerry Kline of Sea Tow Central Florida Lakes. "I met a Sea Tow member who had 95 hours on his engine and was waiting for it to hit 100 hours before he did the maintenance," says Capt. Kline. "The problem was, the last time the engine had been serviced was four years earlier, when he bought the boat."