Thanks everyone for the input on my mower problem. I opened the governor and it continued to back fire and stall so I checked the fuel lines and fuel pump everything seemed o.k. Next I checked voltage and was good but I had corrosion on terminals and battery so I cleaned that real good. I started the mower again same problem. I wiggled wires, checked connections and looked behind dash and decided to unplug the pto switch and there was come corrosion on plug I cleaned that and lubricated it and decided to try it again and engaged the pto no backfire, no stall, the mower engaged perfectly. I don't know for sure what I did to correct it but it seems to be working fine as I cut 1/2 acre grass later. I bought this new in 04 and it has been well maintained with oil changes every 25 hr. Maybe it will last another 900 hrs. Thanks to all who took out the time to respond to my problem. Thanks,JTM