Man I'm hoping someone here can help me diagnose this. I have a Troy-Bilt GTX20 Garden Tractor (Model 13706). When the mower is started (cold) the PTO will engage fine. After a relatively short time with the PTO engaged, it will either cut out completely or the RPMs will drop extremely low for a minute or so until it stops. Once the mower has sat for a while and cooled, the PTO will engage again, but shortly after I have the same problem. There is also an odor as this process happens, which I believe is either electrical or metal on metal. I've already ruled out any problems with the electrical system/wiring UP TO the coil. I'm almost certain the problem is either with the PTO clutch or the coil, but I don't know how to diagnose which it is. Two additional pieces of information: The battery is being drained fairly quick and there is a fuse connected to the PTO switch which will occasionally blow. Neither of these problems presented themselves until the PTO issue began. I really need someone to come through on this. I have 4.6 acres to maintain. New PTO is around $450 and coil around $250 (best prices I could find on the Net). I have a new baby and can't afford to just buy parts HOPING it will solve the problem.