OK, Just trying to find out what might be my problem with this Engine. I have a 3W 150 TOC engine in a SD 40% YAK. It has baffles in front and rear of the engine for cooling. Problem. when running at full throttle on level flight for about 2 to 3 minutes the engine will automatically shut down like you throttled back to 1/4 throttle, if you move the throttle up and down between 1 quarter an full the engine does not change but If you move the throttle stick all the way back to idle then back up again it will run at full power again for another few minutes and do it again. If I run at 3/4 or 1/2 throttle for 2 to 3 minutes then try to go to Full power same thing happens, need to bring the engine back to Idle then it will respond

Here is what I have checked so far.

Engine has cooling baffles. Checked engine temp and got readings of 160 to 173.
Carb has been completley cleaned out so no debris in the Carb.
Tank has Large tubing and no kinks so fuel is not an issue.
Needles (H end ) is bout 5 turns out just to make sure engine is reach, Low end is about 2 1/4 out. If we turn the H end in to 2 .5 turns it goes lean. ?
prop size is 32x10