A picture of a man stressed out because his RC Car is broken

Why Does My RC Car Rev High and Then Cut Out?

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Why Does My RC Car Rev High and Then Cut Out?

I have had this happen to me with every single nitro RC car I have had and I can honestly say that the problem is the mixture. Your RC car will have a couple of things you will need to adjust to get it running properly.

RC Car Mixture Needle

This is usually a small screw with a spring load and is located at the top of the carburetor. As you tighten the screw you will find that the fuel mixture becomes leaner, tightening too much will starve the engine of fuel, too little and you are letting too much in.

You will need to move the needle in small increments to find the best mixture for your particular RC car. This can take a little time and sometimes you might find that your needle will need adjusting every time you take your RC car out.

RC Nitro Engine

RC Car Air Filter

The air filter can become dirty quite quickly and should be washed in hot soapy water every now and again and left to dry naturally. If the air filter is split or damaged in any way you should consider getting a replacement.

The air intake is very important, and you could be starving the fuel mixture of air. this can also make your engine idle and then cut out.

RC Car Exhaust

Often overlooked the exhaust can be a problem if there are any obstructions or damage to it. If the fumes cant escape adequately then the engine may “bork” or cut out unexpectedly.


If you live in a climate where your temperature fluctuates quite a lot, like in the northern hemisphere. You will find that your mixture will need checking on a regular basis. When getting into the hobby of RC Cars, people don’t realize that the outer elements do have an effect on the chemical process of nitro engines.

I welcome this as to me it is part of the hobby, tinkering with the engines and trying to get the right mixture. If it’s not something you want to do and would rather just get out and race then maybe an electric RC car might be a better option for you.

I hope this has helped those that are having problems with their RC cars cutting out or idling to high!