Hello,
I have a John Deere 14SE walk behind mower from the mid 90's that I acquired a year ago or so. Can't believe how solid this thing is built, but unfortunatly I can't get the engine, a Kawasaki FC150v, running properly. It starts right up, runs great for about 10 minutes, then starts stumbling. The engine seems to be getting too much fuel, or the electrical system is breaking down. I have had the carb off and apart many times, it is clean, even took the carb to a mower repair shop owned by a friend, they took it apart and could fine no problem with it. The carb and choke linkages are adjusted fine, the carb float seems to be working fine, the needle seems to be seating properly. Have tried many different brand but proper new spark plugs with the same results, they all turn black right away. Tested the OHM resistances in the coil, both primary and secondary as per the John Deere manual, and they are right on both before and after the stumbling conditions occurs. I replaced the fuel line, made sure everything was clean, but like I wrote, when the stumbling occurs it looks like an over-rich condition. Tried loosening then actually replaced the gas cap thinking there may be some type of vapor lock due to the gas cap to no avail. I am usually pretty good with these things but I gotta admit I am about to wit's end with this one. Anyone have any suggestions? Thanks.