If for example your nitro engine runs fine but does not move that signifies something in the drive train has come in lose. Best course of action would be to initially check out the rear wheels. Ensure in the nuts which fix them to the axle are tight. If nuts are free then the axle will probably keep turning in its place but the wheels may not get the gear to move.

If rear wheels and their attachment to the axle is okay then it would be a good idea to check the inward drive shafts to the differential case. If there are universal joints at the differential case, they're attached with small screw sets. These screw sets may be causing the problem as to why the car remains static, they hold the drive joint onto small stub shafts which project from the case. If these shafts are loosened then the stub shaft will spin around but the drive joint won't. The set screw will need to be on to that flat portion of the shaft to align the same with the drive joint. To get access to the set screw it may be neccessary to strip the suspension slightly.

Again, if the car starts and is running okay but the trouble persists, it could possibly be that the primary gear needs inspection. Check the main gear to ascertain that it is secure on the shaft. If a slipper clutch is loose, the main gear will rotate but the power won't be channeled to the gear box. This can be easily seen when the engine is operational. If you see that the gears turn but the shaft doesn't then it means that the slipper clutch is loose. The main gear needs to be tightened up on the shaft and the problem should be solved.

These suggestions are more effective with the nitro powered model cars but not limited to them only. Implementing the above inspection rules should clear any problems with most cars.

Problems such as these occur largely with nitro powered remote control race cars and are due primarily to the vibration of the engine which tends to slacken the nuts, bolts or screws to the chassis etc. Although the initial working model might have been perfect it is always advisable to check and conduct regular maintenance to avoid such problems in the future.

A good rule of thumb would be to run a half hour inspection to the model after every 4 - 6 hours of use. This maintenance always keeps the model set right and ready to race. Generally Nitro models need a reasonably high level of maintenance, due largely to the speeds attainable for example an 1/8th scale off-road single speed will average 30-40 MPH, while a 2-Speed averages out at around 40-50 MPH. Trucks of course are heavier and therefore not just as nimble yet nevertheless can manage speeds of between 25-35 MPH. Speeds are of course variable and dependant upon environmental conditions, engine size and so on.

Consequently providing a nitro engine with the attention it requires along with regular maintenance will greatly help and prolong the performance of the model, keep running costs to a minimum and give many more hours of racing.