Had the 650 out two weeks ago and it ran fine. Put it in today, fired up and ran tope end no issues for about 20 or so minutes. Then it began bogging at full throttle to the point I had to let off. It idled ok. Turned it off and restarted and it took off again well for another 10 minutes, then the same thing happend. it did this all the way to the dock. One time it died while at top end, but refired and took off again. Does this indicate a thermo switch issue?? Any ideas??