So I am relatively new to gas engines, going on my third season with gas. I have seen two types of fuel line. Tygon yellow but it comes in two types. One is clear and stiff, the other is milky yellow like glow line and softer. I have found that the clear stiffer is cracking and gets really hard in cold weather. I really haven't used the softer stuff. I have had the clear line crack on me and I am trying to find the best gas fuel line that wont crack. Any suggestions would be great.

Here is what I have been using and it has been cracking.
Sullivan fuel line.

This is the softer silicone from dubro, never used this stuff.


Here is what has been happening with the Sullivan clear line.



So what is the best fuel line to use on gas?

TB

Tygon is a trade mark of a vinyl based tubing mfg. by Saint-Gobain Corp. It is made in many formulas but the yellow formula commonly used for our engines is F-4040-A. Every piece of real Tygon F-4040-A line that I have seen had the TM Tygon and F-4040-A clearly marked on the side of the tubing. That is the easiest way I know that you are getting the real thing. This same tubing is packaged and sold by other companies such as Oregon and perhaps Stens for the chain saw and lawn equipment trade as well as by several model companies. But .... it is always clearly marked Tygon with the correct formula number right on the tubing. I have used the DuBro tubing before and it was clearly marked as stated.

I have never seen real Tygon crack and fail like the line in your photo. Further, real Tygon is not usually quite that transparent. Makes me wonder .......

Of course there are other types of tubing that are also popular and I have tried most of them with mixed results. Viton is pretty much bullet proof for our applications with excellent fuel resistance and is much more tolerant to heat than yellow Tygon. It lasts forever as a clunk line but the commonly available sizes are not quite as flexible as Tygon when it is new. I like if for clunks in larger tanks but find it too stiff for smaller tanks. I'm told that Stihl markets this line in smaller sizes but I have not checked this out yet. The biggest drawback of Viton is its cost.

There is a Tygon formula made of polyurethane that works well for our use. It has excellent chemical properties and good flex. I've used some of this and can't find any disadvantages of using it other than I found it a bit hard to get onto fittings .... especially larger fittings like some carbs have. I've found it has to be heated quite a bit to allow it to go on these larger fittings. Once on, it has to be cut off which isn't a bad thing really! It is cheaper than the regular yellow Tygon. One of the regulars on this forum sells this tubing and maybe he can expand further about its advantages.

Overall I still use the regular yellow Tygon for everything outside the tank as its never given me any problems. I usually change these lines every 5 years or so but they are still serviceable at that time.

Thanks for all the info. I checked the tubing I have, the Sullivan does not have the logo on it, the Dubro does. I will try the Dubro Tygon over the Sullivan. The Dubro is softer and more flexible so maybe that will help.


TB


TB

MTK,

Why aren't you responding?

I thought we'd hear from him by now. His product is good but like everything in life, everything has its pros and cons. I didn't buy my poly line from him but did order the number he posted from a common commercial source.

Yeah, he is usually onto a post like this like "Flies on..... well, you know." What's up MTK?

AV8TOR

Tony,
This is the line i use, it stays soft and flexible for a very long time http://leisurercmodels.com/other-products.html scroll to the bottom of the page.

Thanks Steve, I will try this line on my test plane for breaking in the engine.

TB

Not paying attention....No biggie tho. Truckracer stated the virtues of the tubing very well. No need for me to add anything. Seldom do you find something that's terrific and inexpensive at the same time.
If anyone needs some of this tubing contact me direct pleez...

MTK,

I think we were all worried about you.

i ordered some of this same tubing from http://www.taildraggerrc.com/medium-...id-20cc-170cc/ i plan on using this for the external lines, and Viton for the clunk line in the tank

Thank you. I am still here thanks God, and hope to be for a while yet.

BTW, the tubing I use and sell is equally at home inside or outside the tank.....