I have a MF 220-4 1980. I was blowing out my driveway for about an hour and then all of the sudden she died. Won t restart. Bleed the fuel system air in the lines; get it to run for about seven minutes... dies. I replaced the fuel filter and all of the fuel lines and it s still doing it. Seems like vapor lock! It s a gravity fuel system. After it dies fuel will not come out the bleed screw. Takes some time to cool down and it will bleed... bleed the screw, get the air out... bleed the injectors.... eventually starts. Runs for about 7 min and DIES!! This makes no sense to me. Please help! I need this thing to work the snow is getting deep!!