Question: What Size, Length, And Color Of Fuel Tubing Is Best?

Although silicone tubing used in nitro glow engines has many auxiliary uses, it's primary use is to deliver fuel. A typical nitro engine has two lengths of tubing. One runs from the fuel tank to the carburetor (sometimes with an inline fuel filter in between). Another piece of tubing, called the air pressure line, runs from the fuel tank to the exhaust or tuned pipe.

It helps to pressurize the fuel tank so that the fuel flows better through the fuel line to the carburetor. See closeup illustration of fuel tubing and nitro RC fuel system.

Answer:

Nitro RC fuel lines come in different lengths and diameters. Inner diameter is the most critical measurement because that determines how much fuel can pass through the line. Generally it is best to stick with the stock inner and outer diameters of fuel tubing specified by the manufacturer of your nitro engine.

Fuel Tubing Size

Size isn't absolutely critical because you can adjust the flow to some extent; however, tubing that won't allow enough flow even with the needle settings wide open isn't going to deliver enough fuel to run your nitro RC reliably. If you try to run your engine with a larger or smaller diameter of tubing than the manufacturer specified you're likely to need to spend more time leaning and richening the fuel mixture because the tubing is letting in too much or too little fuel. You'll also want to be sure you use fuel tubing with an inner diameter that fits snuggly to the fuel tank, carburetor, and exhaust fittings.

Fuel Tubing Length

You might want change the tubing length if you need to reroute the fuel line.

Usually the stock configuration of the fuel line works well. Where the fuel line goes around the heatsink head of the nitro engine there will be heat resistant shielding material to prevent the tubing from melting. Don't remove this heat shielding material from the fuel line. Nitro fuel is very flammable and could cause serious injury if given the chance to ignite.

Fuel Tubing Color

Tubing color is simply cosmetic. You can change the color for a custom look or to color coordinate with other components. Tubing color doesn't affect the stock mixture setting of your nitro RC. You might want to use different colors of tubing for the fuel line and air pressure lines to differentiate them better. If you're having engine difficulties or when your nitro engine is new and still in the break-in stage you might want to use clear tubing so it's easier to see the fuel flowing.