Friday I was mowing with the 140 for the first time since it was re-built. It just didn't seem to be producing the power it should. When I put the tach on it, I only got a little over 2900 rpm. I went over the governor settings and it seems to be a carburetor problem. It's running smooth, but the most I can get out of it is about 3100 with the throttle shaft against the stop. The throttle shaft is pretty badly worn, REALLY loose. Could that be the cause?