I am new to boating and motors. I have a 1994 Cajun 18 ft with a 135 Mercury. I had the motor checked out and serviced about a month and a half ago. The impeller and alarm control module were replaced and the oil injector pressure checked out good. I took it out for the first time last weekend and all went well until about 4 hours into the day. I started to get a weak alarm about mid throttle and after a about 2 seconds it got louder. Cant remember if it was steady or on and off. This only happend at mid throttle... If I opened it up the alarm stopped and if I slowed down the alarm stopped.....Just went off at mid throttle. The boat has been unused for about 3 years and I do know that it has a new power head on it with about 19 hours of runtime. <br /><br />Any advice<br /><br />Mark 