Hello everyone. I hope someone can help. I recently got a 24 ft. Pontoon with a 40 HP 1987 Yamaha outboard motor. After a few times on the lake, I started having problems. When I had it wide open at full throttle, all of a sudden, it would slow down. Then it would speed back up. I have given the motor a tune up, but it did not help. Then out of the blue today, it started going really fast. Faster than it ever had. We thought maybe it had had a clogged fuel line that finally got unclogged, and then of course it slowed back down. It was very windy this weekend at the lake we were at, but it really seemed to go through a lot more gas than usual, however we only got to go "fast" for about a half hour, so I do not think that caused all the gas usuage. Does anyone know what could be causing this? We obviously know now what it is capable of, but why has it never went that fast before and what is making it lose its throttle?
