2004 90hp Mercury 2 stroke – When I give it throttle, it wants to die. I have to move the throttle several times back and forth quickly to get it up out of the hole. Also, after running wide open for several minutes it loses power. It has a mind of its own. It jumps around from 5000 rpms down to 2000 rpms. I have brought the motor in twice to the same repair shop and they say nothing is wrong. They have changed fuel filters – but it still doesn’t run right.