Hi Ive kept this cart running for several years. This time I can`t keep it running. I replaced the fuel pump. It had a cracked diaphram. It will run if I fill the filter up with fuel. Will run as long as I have the rear wheels off the ground. When I drop the jack It seems not to run strong enough to pull itself. Does the fuel tank need to be under pressure? Has great spark. Ive cleaned and re-adjusted float. I adjusted it to coming out of overflow then backed the float so it doesnt come out of overflow. Im baffled unless the fuel tank must be under pressure because the tank float seal and fuel line valve seal are not great. Any ideas? Thank you! I adjusted the air/fuel mixture screw out 2 turns.