I bought my boat nearly two months ago it is a 1988 Sportcraft 205 with a 140 hp OMC mounted on a Seadrive. The first time I took it out the overtemp horn would sound when the rpm exceeded 3500, but the power was fine and the boat planed out at 5500 rpm. After my mechanic replaced the waterpump,replaced the head gaskets the electronic unit and the number three coil. I thought that the boat would be ready for a long summer of fishing of the coast of San Diego. The first trip was a test Iwas happy that the overheat problem was fixed, but I could not get the motor past 3800 rpm and the speed maxed out at 12kph with the wind. My gas milage was less than 1 mph. Back again to the shop and my mechanic says that after lubricating the timing advance plate the boat ran fine. That was not case on the next trip out to the Coronado Islands<br />The boat ran okay for about fifteen minutes of the whole trip just long enough to make me beleive that it would be good enough to take into blue waters. That trip was 40 miles on 45 gallons of fresh gas. My boat is back in the shop and it has the mechanic stumped. Full throttle only 3800 rpmall electronics tes good and carbs seem to be fine? Whats up ? 