by Greg
(Saco, Me.)
I have a 98' Yamaha 9.9 4-stroke when you first start it idles fine, after a minute or so it idles way up on its own. Also when I am using it it will be running fine and then all of a sudden it will idle up really fast and then go back down to normal. When moving and it idles up it does not push the boat any faster then it was going, and it almost sounds like the motor is cavitating but it's not. Any help would be greatly appreciated?