Since it's brand new you need to break the motor in. (look in your manual which should tell you the recomended procedure) wats happening is the piston is getting lock from too much pressure and stuff. just take the glow plug out with a nut driver, let the fuel get out by pulling the chord a couple times and for a while, spray wd-40 in the engine and pull on the chord for pretty good long time to help wear it in a bit. then put the glow plug back in and try again, repeat if needed.