The engine has to be Run-in before full-time use. It is very important that this procedure is carried out. Not doing so will shorten the life and reduce the overall performance of your engine.
There are two different methods people use to run their engines in. The first one is simpler and is also safer in that you are less likely to burn your clutch out or something if you get it wrong. With the second method it is more complicated but if done correctly will give a little more life to your engine.
To run your car in, take your finished model and roll it back and forth to be certain the car's wheels can turn freely. Place the car in a position so that the wheels are off the ground, for example on a heavy box or brick, and follow the starting procedure which can be found on our help page. Use good quality fuel with around 10 - 20% mix. Its best to break-in the engine using the same nitro content as you plan to use for everyday use. The engine should be broken-in on a smooth hard surface. For a boat engines, try to find smooth clam water. Try to avoid breaking-in the engine on very hot, or humid days. Ensure that the idle speed is not to high or else you will burn your clutch out or snap the con rod, and also make sure that the brake is not applied.
Always break-in your engine without the body on the car, you want as much airflow as you can get to keep the engine cool. Do not run the engine too lean or you will over heat it and cause permanent damage to the internal components of the engine.
It is normal for the engine to consume a lot of fuel during break-in. This is because you are running it "richer" than you normally would to keep the engine cool and to flush out the engine as the parts "seat" themselves. Because of the richer than normal setting the performance of the engine will be limited. After break-in, you will then lean it out to gain performance.
It's always a good idea to get an extra glow plug (short, cold plug). It is normal to have to replace it after break-in because of the deposits left on in from the break-in process. Glow plugs are a normal item that needs replacing. Because they have such a huge influence on they way your engine runs it best to always have a few spares on hand.
Once it starts and is idling slowly place it on the ground and drive it slowly on a flat surface. For the first use do not let the engine run for more then 3 minutes. Carry on running slowly for short periods until you have gone through 2 - 3 tanks of fuel.
With method 2 start the car in the same way but when it starts instead of placing it on the ground keep it off the ground and let the engine idle through 2 - 3 tanks of fuel. Let the engine cool down in between each tank and lean the engine off as needed. Do NOT rev the engine while it is running in and be careful not to lean it off to much or else you will burn your engine which would not be covered by the warranty.
Do not over accelerate at all during this procedure, as it can severely damage the engine. After each idling time, let the car rest for about 10 minutes between each tank. Running in makes sure that the engine is operating correctly before you take it out for a proper run. Never accelerate the engine while all four wheels are off the ground, as this will break the conrod or other important components.
One important thing to remember when breaking in a new engine, it will appear to not run correctly. It will stall, operate very inconsistently, and may even foul glow plugs. Don't get frustrated with it. Just keep working with it and it will become a smooth running engine. These experiences are what can be called "break-in pains". Every new engine has to go through this. When you get the engine started, be sure to keep it running by giving it throttle when it sounds like it's going to stall. Pulling the throttle quickly can also stall the engine. After a couple of tanks your patience will pay off with a very strong, reliable running engine.