Same fuel my old engine was running on three days ago. I drained all three filters on the side of the road and got nothing but clean fuel out. Had good fuel pressure, 30 psi idle and up to 80 under acceleration. Then it just started acting stupid. I really feel like something is hung up in the governor. I may pour a gallon of kerosene in with the oil and spin it over for a minute to circulate it into the injector pump and see if it'll free it up after sitting a while. I didn't want to have to work on this motor. It is so clean, almost like it was never ran. No oil seeps, no peeling paint, no rusty anything anywhere. Very clean inside too. I pulled the FDC on the side of the road to see if the linkage in there was free, and it was. Pulled the shutoff cover and it was all free. Tried to crank it with the shutoff cover off and still no luck. Got a ride home and went back with the M936 and just drug it home. Plenty of smoke when I'm cranking it, and it tries to start, then the smoke will stop and if I keep cranking it will come and go, but won't fire and run unless I spray some brake cleaner in the air filter.