86 mercruiser 470. Had boat out all week and was running great. Today after about an hour or so on the water, I opened up the throttle, got to almost top speed and the engine just shut off out of nowhere. It started right back up, but now she wont let me give it any throttle without stallling. It runs fine in gear at about 5-10 mph but if i open the throttle it will begin to plane off then hesitate and stall out. Any ideas??? Im a new boater, so it could be something simple. Yesterday, with some advice from a fellow boater, I added soemething called startron to the gas(just a few ounces). Not sure if that had any ill effect or not. Boat also has an electric fuel pump installed.
