This engine runs fine until about 1/2 throttle then it acts like it wants thow it self off the transom. I mean really rough running and no power. I think it is locked in SLOW mode. It does the same thing with a water hose connected. So load or no load the results are the same. I checked the temp switchs they are both open. Could this be a power pack problem. It has a new trigger and rebuilt carbs.

Thanks in advance for any help on this..