I asked you if it was Ringed because I am trying to help you. an ABC engine is very tight, so it may take many runs before it runs correctly.

but first, please, please, get rid of that so called "special" glow plug and buy a quality plug, if you engine takes a short plug buy an OS #7 to start with, because your engine is so new.

another thing, a glow engine, any non E ignition glow engine needs to be loaded correctly for it to run correctly. a prop makes a very good flywheel. but from the photos I have found on the net of the Mavrick's clutch system it looks to be very light. this light clutch gives your engine very little "Flywheel Effect", this, along with running your engine without loading it with blades is good reason for your engine to sputter as you raise the RPM from idle.. a hotter plug will help (specialty with braking in) because a hotter plug will burn more fuel at lower RPM.

14 year old fuel certainly can be questionable good or bad. try fresh fuel.

Jim