I have a m700 with the vh4d when I go to full throttle it will run for maybe a minute then sputter and die sometimes the gov will hold it and bring it back other times it wont also it will back fire. ive replaced the plugs, cap, installed an electric lift pump (the mechanical one was leaking) ive adjusted the gov a few times, ive replaced the fuel filter after I pumped out most of the gas out of the tank and put 5 gallons of fresh gas in it. ive adjusted the idle screw and it doesn't seem to make any difference. I'm looking for any new ideas here the factory service manual isn't very good for troubleshooting.