I start it at my dock, it runs perfectly, then I go about a mile at fast idle to go fast zone.
I then trottle up to try to plane off and the engine just sputters an falls on it face..
It will not go any faster, just sputters untill I trottle back then it runs great at about 1100 rpms or so.
Then I turn off key and it a couple fo secomds restart the engine , put it in gear , hit the trottle very hard and the boat jumps up and runs up to 30 mph ao so like it should . I then run between 20 and 30 mph it runs fine.
If I the pbring it to an itle and hammer it again it usually runs up to top end with very little surge.
I have a 2004 yamaha 115 four stroke o/b. on a 19 ft center console Key West.
Whats the problem ?