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Let’s Talk Fuel Lines! — Care and Feeling for Reliable Performance

Make sure to use zip ties on all fuel lines for maximum safety

On all of my nitro and gasoline-powered airplanes, I use zip ties to secure my fuel lines going from the fuel tank to both the carburetor and the muffler. When routing lines within your airplane, make sure that they can move freely and are not bent in any odd fashion. After all, you need to make sure that fuel can move slightly from the tank to the carburetor, and also, from the vent line in the tank to the vent on the exterior of the model. However, make sure that these lines do not come into contact with any hot item like the engine’s muffler. Rather, fasten a line if you think it may touch the muffler.

Also, if you are flying a gasoline-powered airplane, make sure that you change all fuel lines yearly. In the past, I have put airplanes aside for a year or so, but I always perform a pre-flight check on my airframes before taking them to the flying field.

In this routine check, I go over the fuel lines. On occasion, I have found that gasoline lines harden, and in fact, the clunk line can harden. I have heard horror stories where people have experienced an engine failure while the airplane was inverted and they lost that particular model. The cause– a hardened clunk line that did not fall freely within the tank. As a result, fuel could not reach the clunk and the airplane’s engine quit at a rather unexpected time. Simply said, make sure this doesn’t happen to you!


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  1. Tygon doesn’t ever belong INSIDE the fuel tank. Try the black tubing rated for gasoline. Its more flexible and does not harden.

    Put the correct size tubing on your fitting or use the right size fitting for the tube. Your T in the picture is a good example of THIS IS WRONG.

    1. The above photo is the worst example fuel plumbing I have ever seen, another self appointed expert?

  2. what type of black tubing?

  3. Viton black tubing! Never hardens!

  4. The ethanol in pump gas caused hardening of lines and carb diaphrams..i will not run pump gas

    1. I use the Non-ethanol 91-Octane, but first I pump a gallon into my van, then I pump the amount of non-ethanol gas into the gas can I mark for Model Use Only. That way I clear out the hoses at the pump and do not get a mixture of Ethanol and Non-Ethanol fuel into my model gas can mixture.

  5. Tygon is perfecty fiine in the tank for gasoline and jet fuel, BUT it is important to leave some fuel in the tanks to prevent it from hardening… Instead of zip ties I would reccomend wire tiring instead.. I have tygon in tanks that are over 5 years old no problem!

  6. Neoprene tubing, although there a a few different yellow ” tygon style” tubes that vary in chrome get don’t use it in the tank unless you got a 5 ounce clunk. Way too stiff to work nicely. Small engine shops might have Still fuel line…..awesome stuff.

  7. I can’t believe MAN is still promoting the use of cable ties on fuel tubing connections. It has been well known for a long time that although they may stop the tubing coming off they can and do cause leaks. This is becuase they do not squeeze the tubing around its entire circumference because they have a 90 degree angle where the end passes through the lock. If you want a simple and cheap method cut a 1/8″ length of the same fuel tube and use needle nose pliers to slide this over the top of the fuel line connection.

  8. I believe Jeremy Randle has the best way to safely secure fuel lines. Thank You Jeremy…. I am going to try your doubling over technique. Glad you posted that. Makes sense to me distributing the holding pressure around a larger area equally.
    Thank you again.

    Michael Reiman, Gas Beach Flyer
    Palm Beach, Florida

  9. This doubling over is the best, a rc buck guy showed me this 20 years ago for glow fuel line. I did go to the large blue line as it is much stronger than your basic standard size line.

  10. Viton tubing is the only type that should be used inside the tank. Make sure the fill clunk on the third line is shorter than the carb clunk to keep them from interfering with each other. If the carb clunk can bend forward to the front of the tank,insert a short piece of 1/8″ brass tubing(ends rounded) into the line to stiffen the center portion of the tubing. Allowing the clunk to fall forward is asking for trouble when it gets stuck there. The doubling of a piece of tubing works great for securing the tubing as well as a double wrap of wire and twisted tight. 3 tight loops of fuel tubing after a fuel filter on the carb line can equalize the gravity effects on 3D type planes that tumble a lot. Just use 2 plastic tie wraps to hold them in place. Never decrease/increase the size of the carb line with filters or tees that are not the same as the tubing being used. The vent line should make a loop or 2 around the outside of the tank before plunging through the bottom of the fuselage to keep the siphoning action from spewing fuel out of the vent line. Keep this in place with plastic ties connecting it to the fuel tank tie downs.

  11. Thank you for the fuel line tips. I really appreciated the knowledge and the why’s of gas powered models. 🙂

  12. Anyone ever tried mounting fuel tank inside fuselage, then running tubing out thru wings to carbs if twin engine planes ?

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