Hi Terry,
I`m watching this post very carefully
As same same issue with my motor
I have noticed that if I let the motor idle for a few Min's and then nail the throttle, I have full power again for a while before the revs start to drop off again.
Out of interest what plug are you using? I have a NGK BR9ES currently filling the hole, which is possibly a little cold.
The US corsair site recommended Spark plug types: NGK B8ES (for normal or hot climate) and NGK B7ES for cold climate, might just make a difference .
Colin B