ORIGINAL: cold_reboot

I'm willing to bet your piston got stuck at top dead center since it's new. Heat it up with a heat gun, or if you don't have one, a hair dryer. You can also use a small screwdriver to break it loose by using the screwdriver on the flywheel (flywheel should have some shallow "teeth" on it. Use the screw driver as a lever against some part of the chassis). It's not uncommon for a new engine to get stuck at top dead center when they are new due to the "pinch". Since nitro truck engines aren't ringed the cylinder is tapered toward the top of the stroke to create compression, this is referred to as "pinch". You may need to preheat your engine with a heat gun or a hair dryer to expand the cylinder so the pinch isn't so tight until you get it broken in. Preheating also puts less stress on your con rod and other internals with that tight pinch when it's new.