I have even put a loop in the fuel line to the carb to help against the siphoning effect. My inverted MVVS .25 does not take well to a prime. It will flood everytime. I just flip it by hand a time or two, with the lines disconnected or throttle at idle, to make sure it is not locked up with fuel before I put the starter to it. Also, be careful removing the glow ignitor, it is a different beast to get at under the plane. Maybe try a remote glow system.