I just bought a 96 Tracker Pro 18 boat with an inboard jet engine. I'm new to boating and do not know a lot. I believe it's like a 85 hp. When I have it at full throttle it dies down. It will not go any faster than 15 mph for more than 30-45 seconds. It Boggs down and eventually shuts off. There is white smoke coming from the jet. Not sure if it's bad gas from just being filled up from sitting for awhile or if it may be something else. .