RC Carburetors

A graphic look at a slide valve three needle R/C Nitro Engine Carburetor.

All r/c nitro engine carburetors are of the slide or rotary valve design.

This pictorial is of a slide valve r/c nitro engine carburetor. A large number of slide valve carburetors are of the three needle design.

A high speed, low speed and idle adjustment needle. There is some variance in this, some use only two needles.

While others use three needles, just that the manufacturer's use different terminology.

Now let us take a closer look at a r/c nitro engine carburetor. A graphic guide to all the parts that make up a r/c nitro engine carburetor.

Radio Control Nitro Engine Picture

Radio Control Nitro Engine Picture

Understanding your r/c nitro engine carburetor is very important.

Learning how to adjust your carburetor to critical in getting your r/c nitro engine to perform correctly.

Adjusting the high speed needle or screw either lean's or richen's your nitro fuel mixture entering the r/c nitro engine.

Adjusting this needle controls the temperature your engine is running at. Plus, it affects the overall performance of your r/c nitro engine.

Too some degree adjusting your high speed needle can change how your engine idles. It can be an art or science getting your r/c nitro engine carburetor adjusted properly.

Be patient and only do adjustments in small increments. A 1/16th to 1/4th of a turn.

I usually start at a 1/16th of a turn and see how that works and keep adding a 1/16th of a turn till I reach the tune that suits me.

So do take your time and keep notes on what adjustments you are making.

Radio Control Nitro Engine Picture



One other tuning factor that affects your r/c nitro engine is the carburetor restrictor.

Depending on which r/c nitro engine you have you will more than likely have two or three restrictors included with your engine.

The sizes of these restrictors will be from small, medium to large.

The actual millimeter size will vary depending on the size and manufacture of your r/c nitro engine carburetor.

The restrictor you use will depend on your driving style and how you have your engine tuned.

Just remember that changing the restrictor will require you to re-tune your r/c nitro engine carburetor.