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Stock Fuel System Questions.


Registered User
Justin, TX
2 Questions for all you experts!!!!!!

1) In studying the drawings of the stock fuel system, I just want to make sure that I'm understanding the drawings correctly, I read it as follows. Right tank, 1 line goes from rear tank fitting to rear header tank (fuel supply), 1 line goes from rear header tank back to right tank (vent) which tees to top of site gauge both lines go up to tank through right rear behind d window, 1 line then goes from header tank to fuel valve. Left Tank, 1 line from lower front tank fitting to front header tank (vent line?) through front left window post, 1 line from front header tank to tee at fuel valve, 1 line from tee at fuel valve up through rear left window post to rear tank fitting (fuel supply) and then the 1 line from the valve to gascolator.

I hope I explained that ok above, I was surprised to see that the vents on the right and left systems were connected to the tanks differently. hence the question.

2) When replacing the fuel lines from the valve to Header tanks/vent lines to tanks Etc. do you guys prefer to make your own lines or is it best to buy the pre-made ones from Univair or other sources?

I make my own lines, it's easy enough, and I think you got everything right on the connections. A few Cub Clues ago I tried to explain the stock fuel system as best I could.....
Thanks MD,

I guess I should have looked at the Cub Clues first. Then I would not have had to ask... In issue # 134 you had a great article, I just read it...I had not read that issue yet so I guess I missed it...


If you make up your own lines what tubing do you use?

Per the Piper drawings lines appear to have been made out of 1/4" and 3/8", 3S-0 Aluminum tubing which appears to now be 3003-0 aluminum tubing, I found on a search here that 5052 tubing was recomended. I think the 5052 is rated for higher pressure and more rigid lengths as opposed to coiled 3003-0.


I use 5052 except some areas where I need to do some really tricky forming which has not been on Cubs. Use a spring type plumbers tubing bender. Easier to use than the vever type on what you will have to do on a SC.
I've had the 5052-0 corrode fairly fast, and it is tougher to work with, so now only use the 3003-0. It's not like I need a 5000 psi bursting strength fuel line on a Cub.