My '95 bayline/mercruiser i/o gets no thrust past 1500rpm after about 5 minutes of use. Engine sounds great. I can leave the shifter untouched and it will accelarate uncontrollable w/o speed or thrust. I can't drive more than 5mph.<br /><br />When I try to slowly accelerate, I hear a low, grinding noise below, then at about 2000rpm no additional speed just the roar of the engine.<br /><br />I have had the prop re-shaped, cables adjusted still same problem. Please help