C115 Yamaha 1998

by Buddy
(Louisiana)

Motor starts up like normal, runs fine when throttled to get out of hole, gets on plane, running at cruising speed (3000 to 3300 rims) . After about ten minutes I would ad more throttle 3500 rims+
And the motor would start sputtering and coughing and shutting momentum down!
I've changed every gas line , filter, gas tank, fuel pump on motor, separate fuel tank and line etc.
Still doing same thing. I'm thinking that when she warms up after 10 minutes or so something goes awall! Wth is going on??????