What pulse you get from the crankcase vent is pretty weak from a 4 stroke because of the crankcase vent, it might not be enough to work the pump diaphragm in the carb..The Walbro made for a 4 stroke has a small spring on top of the diaphragm to assist the pulse...The glow carb will work but get really sensitive when using gas..The Saito will run just fine with ignition and glow fuel..