Engine is a MDS .40 FS-1 Pro,prop is 10x7,Plane is a Hangar 9 Xtra Easy.Plane was bought used...never flown by me so the engine problem only has been on the ground.I have not replaced the glow plug or done anything else to the engine other than fueling it and starting it.I have seen tiny buules in fuel line,and carb is not foaming but there is fuel visible sometimes,In the carb opening that is.