Is The Piston Sticks At Top Of Cylinder (New Engine)?

The piston's tolerance within the piston chamber is so tight that there is no space for the piston to slide to the top. The resolution is to heat up the piston chamber with a wool dryer or heat gun. This will increase or expands the chamber, allowing the piston to slide smoothly, while maintaining superior compression.

Is Nitro Engine Dies As Soon As You Drag It Off Starter Box?

If your RC car is politely tuned, your problem is most likely a loose clutch nut. The clutch nut is what attaches the flywheel to the crankshaft. Burning down your RC car on the appetizer box presses the clutch nut against the fly wheel, making the spin that gets your nitro engine started. However, if your clutch nut is too loose from wear and tear or crash, it won't have the correct mesh it desires to keep the car running once you have removed your car from the starter box.

Does Your Nitro Engine Stall When The Tires Strike The Ground?

A frozen clutch-bell bearing or wrecked clutch-retainer spring is the most probable offender. The rc nitro engines stalls because the clutch is occupied when the engine is idling. When you put the vehicle on the ground and the engine croaks as it is not running quick enough to move the vehicle. The retainer spring or clutch bell bearing are compelling the clutch to be unavailable when it shouldn't be. You'll require examining both the parts and also repairing or replacing as required.

Does Your Nitro Power Plant Initiates Backwards?
This is one of the most common problems, with a simple fix as it is always caused by user errors. You need to make sure you put your RC car on the starter box with the exact orientation and that you put your wires on the accurate poles of the battery.

Your Engine Rate or Speed Increases While Idling?

Highly likely that the low speed needle on the rc nitro engine is set to lean and a good assenting test is to pinch the fuel line and time how long the vehicle’s engine runs. If very less than five seconds it's too lean and if much longer than 5 seconds, it's too loaded.

Source: https://uberant.com/article/442655-quick-tips-to-get-your-vehicles-rc-nitro-engine-running/