Built with Volusion RC Nitro Car | Nitro RC Car Remote Control|Nitro RC Cars|Remote Control Nitro Car|Nitro Gas Car|Himoto Nitro Car|Redcat Nitro Car
You are here:Home > RC Nitro Engine Tuning Guide

Congratulations on your decision to invest in a nitro gas powered vehicle! This RC Nitro Gas Engine Tuning Guide provides important information on how to maintain your new nitro car, buggy, truck, or truggy engine.

My engine doesn’t start - what might be causing the problem?
There are two main causes, a glow plug problem or an incorrect fuel / air mixture.
It is important that the glow plug work properly. When a glow plug is working properly, it will burn a bright orange. However, a bad glow plug will not generate enough heat to burn or light the fuel / air mixture in the cylinder.  The two main causes of glow plug problems stem from a bad glow plug or an uncharged glow plug igniter. Charge the glow plug igniter and retry or replace the glow plug.
Secondly, the glow plug engine must have the correct fuel/air mixture when cranking the engine.  There may be a lack of fuel if the tank is empty of there is a clog in the fuel line. However there may be too much fuel in the cylinder (i.e. engine flooding) which may be caused by over priming.

How do I fix a flooded engine?
The main method to fix a flooded engine is to remove the glow plug without losing the little washer. Once out, turn the car upside down and pull the cord slowly several times to allow the fuel to come out. Replace the washer and glow plug. The engine should start right up without any problems, just prime and restart the engine.

How do I know if the engine is flooded?
The engine is locked up if the pull cord becomes hard to pull. Do not try to pull the cord loose, doing so may break the cord of damage the engine.  Moreover, you can tell an engine is flooded if it won’t start although the glow plug lighter is fresh and the glow plug is new.

The engine starts but stops immediately when the glow plug is removed – how can I fix this problem.
There are two main causes. The glow plug may be faulty, if so replace the glow plug. Secondly, the fuel/air mixture may be too rich. Adjust the carburetor accordingly.

My engine is running too hot, how do I adjust this?
A lean engine will cause a lot of damage. An engine will run lean if there is too much air or not enough fuel in the fuel/air mixture. The carburetor controls the fuel/air mixture. Adjust according to the instruction manual that comes with your engine. If adjusting the carburetor does not solve the problem, chances are the engine has developed an air leak. That means air is entering the engine in places it is not supposed to, such as the section between the cylinder and the exhaust manifold. Another common source of an air leak is the section between the body of the engine and the pull-start mechanism or back plate. Solving the air leak is easy. Disassemble the affected sections, apply a high quality, high temperature automotive gasket sealant, and then reassemble the sections. Make sure to read the instructions on how to use the gasket sealant. A dirty fuel filter will also cause a lean setting. The dirty fuel filter will prevent fuel from reaching the carburetor. Solution is to clean the fuel filter. Binding in the car itself will also cause an engine to overheat. Check that there is no binding in the car by checking how freely the transmission and wheels rotate. It should be easy to push the car by hand, and the car should roll a few feet.

My engine is running to rich, how might I solve the problem
An engine that has too much fuel in the fuel/air mixture has a rich setting. A rich engine setting will also have the tendency to flood the engine, causing it to die. A rich engine will consume a lot of fuel and not generate enough power. The car will run slowly.
The solution is to readjust the carburetor per the instruction manual. A weak glow plug may also cause an engine to run rich. This is because the glow plug is too weak to burn all the fuel. Unburned fuel will accumulate in the cylinder, causing the engine to run rich.

How might I use my glow plug to determing if I am running too rich or too lean?Glow plugs are very important to the performance of your engine, and can be used to check the air/fiel mixture.
A brand new glow plug has a wire or filament that is shiny. If after running the wire is still shiny and the bottom of the plug is wet, then you are running too rich. You are probably getting only 85% of the maximum engine power.
If the wire turns starts to turn gray, and the bottom of the filament is slightly wet, then you are almost near the peak engine power.
Once you have a gray wire, and the bottom of the plug is dry, you are at 100% maximum power.
Once the glow plug wire starts to distort, you have exceeded the maximum power and are running too lean. Adjust to a slightly rich setting.
Hot plugs are used for hot summer days, while cold plugs are designed for cold "winter" days.

My engine isn't old but it's "worn out", why?
Things that cause the engine to wear quickly:
-Improper air filtration
-Running too lean
-Not enough cooling
-Cheap fuel
The solutions:
Improper air filtration... keep your air filter clean and oiled, upgrade to a high performance air filter if you run in areas with excessive dust. You'd be amazed at the engines that we see come in with dirt all over the inside of the engine.

Running too lean... adjust the carb. as often as needed so that you see a nice trail of smoke at FULL SPEED. Running it too lean on the top end will overheat the engine.

Not enough cooling... cut out your body windows according to instructions. If you don't have enough airflow over the head you won't be able to keep the engine cool. It is highly recommended that you purchase some sort of temperature gauge. Engine temperatures over 250F will cause the engine to wear quickly.

Cheap fuel... don't buy $10/gallon fuel that is blended for airplanes. Car fuel is designed for cars, the oil blend is different than helicopters and airplane fuel. Not all car fuels are the same, some have less oil than others. Too much oil will bog down the engine at idle and decrease performance, not enough oil will make the engine wear more quickly. Car fuel labeled "Race" usually has a little less oil, it is intended for maximum performance at the expense of engine life. If you are driving off-road you really don't need a "Race" blend. The fuel is what lubricates and cools the engine, don't skimp on quality.


The engine shuts off when I apply the brakes, how can I fix this?
The main problem may be an incorrectly tuned idle speed screw. See the engine tuning section in order to properly adjust idle speed.


How much smoke should be coming out?
When the car is idling (engine running, car not moving at all), a small amount of smoke should be coming from the muffler or tuned pipe. At full throttle, there should be a large amount of blue-white smoke coming from the muffler or tuned pipe. If you put your hand about 6 inches (15cm) from the opening of the muffler or pipe for a few seconds while the engine is running at full throttle, you should have a light coating of oil on your hand.

What should I do with the air filter?
The air filter is a critical component of your engine. We cannot stress enough that for proper care of your engine, the air filter must be in proper working order. The air filter in all of our Nitro kits is pre-oiled for your convenience, however it must be cleaned and re-oiled after running 2-3 tanks of fuel. To clean the air filter, take the foam filter element out of the rubber boot and use fresh Nitro fuel to rinse the dirt from the foam element. Use your fingers to work the dirt out of the foam. When all the dirt particles are removed (this may take several rinses), squeeze out any Nitro fuel then apply a small amount of foam element air filter oil. Install the foam element in the rubber air filter boot, making sure that the foam is fully seated in the boot with no open spaces around it that air can leak through.

Why won't the pull starter pull all the way out?
The pull starter should only be pulled out about one foot (30cm) to start the engine. It is able to pull out up to 2 feet, but this extra length is only slack to prevent damage to the pull starter spring. If you cannot pull the string out even one foot (30cm), the engine is probably flooded.  See the section on Flooded engine.

My tires start spinning when the engine starts!

Your idle speed is too high and/or your clutch shoes have melted to the inside of the engine's clutch bell (the black metal gear attached to the engine). To adjust the engine's idle speed, see the engine tuning sheet that came with the engine or your kit.

My car is glitching/I can't control my car!

The first thing you should do before starting to run your car is make sure no one is on the same frequency as you are. In the US, frequencies are labeled with a simple number. In other countries, most racers use the last digits after the decimal point to identify the radio frequency they are on. Before running your car you MUST make certain that no one else will be interfering with the radio frequency you are using. After making sure you are on a clear frequency, check these items, in order: radio antenna fully extended, radio batteries fully charged or fresh, the receiver antenna wire is not touching graphite or metal items, the receiver or transmitter crystal is not broken, the receiver is mounted as high as possible on the chassis, or finally the receiver is mounted so the crystal is as far above the chassis as possible. If none of these help, contact the manufacturer.

Related Articles
If this was helpful, you may also want to read other related articles:

RC Nitro Engine Break-In Procedures
RC Electric or Nitro Car, Buggy, Truck or Truggy Buying Guide