Change rubber fuel lines

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Change rubber fuel lines

Postby preacoupe » Mon Jul 23, 2018 5:21 pm

HI guys,

Been a long time since I have been on the forum. Finished building in '13 and all has been good...up until now. I remember reading about changing out our rubber fuel lines every 5 years. Now, Rotax states to do this with the firewall forward, but I can attest to the need for the tanks to the firewall. As you can see from my pics, I had a crabgrass problem while on vacation. Moral of the story is change out lines, or don't go on vacation.

My Escapade was kit #17 first sold in '04. Then, the lines were rubber with hose barbs and clamps...not the most "quality" solution. I switched my lines to fuel injections lines (still rubber) at the suggestion of a Tech Advisor. Supposedly they were more resistant to mogas and the alcohol in it. May or may not be true, but in Tucson, the heat probably did me in. As you can see, at one point there was a failure and both wing tanks drained into the interior of the baggage compartment. It ruined carpeting, foam, paint, header tank, floor boards and the paint on the underside of the plane. Pretty sick, but I'm sure it is just some work to get it all fixed.

Inside, my main concern is to choose the replacement of the fuel lines. What I'm leaning towards is AN fittings and Aeroquip 666 teflon lined stainless steel braided lines from the tanks to the header, header to firewall. I had shutoff valves and filters before and would again in the same places (In baggage area before the header). My tanks are the 13 gallon fiberglass tanks (upgrade from the 9 gallon ones originally) with only the 1 port (low & to the rear). I didn't go with the front pickup, or the ports up high for venting, fuel level sight tube, etc. I guess I'm just not an aggressive flyer as I have never worried about coming in nose down and low on fuel, hence the not needing the front pickup. My questions are about the products listed as the "latest and greatest".

The one plane I can think of that seemed to have a beautiful setup was Troy Branch's. If any of you know what I'm taking about, his whole plane in addition to the fuel setup impressed me. Don't know if the lines were 666 teflon or not, but sure seemed quality. Airfcraft Spruce shows aeroquip lines of 303, 601/701 and others, but it appears they are all rubber lined, which I'm a little leery of right now.

Now, to the paint. Talked with Stewart Systems's Andy. After complimenting me about my ability to destroy a paint job, he seemed fairly optimistic about repairing the paint. The fabric seems still glued to the fuse and is still taut. So, Iffin I can clean the fabric (Ekoclean) where the paint has lifted, I MIGHT be able to just get away with laying down their primer and paint. Bottom won't be as pretty as new but, I just need to get through this and enjoy the plane again. Has anyone rolled on Stewarts instead of spraying? They say it is a method. I could get it to a paint shop and have them do it, as I sure won't be able to paint (spray) in my hangar, and I'm sure not going to bring it home and do it here again!

So, guys, any comments, suggestions on my path out of this mess???

BTW I AM going to do my Rotax rubber replacement ASAP. Saw $1300 on California Power Systems their 5 year kit (all hoses for fuel, oil and cooling)!!!! Wow. I guess I have been away for a while! Also, thinking of the fuel lines from TS Flightlines in South Carolina. These are those 666 teflon/braided with AN fittings. Anyone with knowledge of them or their product? Just, they're in your backyard. Do you know of them?

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Re: Change rubber fuel lines

Postby AV8R Paul » Tue Jul 24, 2018 7:28 am

Your photos definitely support the Hose Replacement mandate from Rotax. I hate to see that, that is going to be a time consuming and costly repair, even doing it yourself.

When I took the Rotax certification training for my Light Sport Repairman Certificate, they said it’s not just the hoses. What Rotax means by Hose or Rubber replacement is that anything that has Rubber: fuel pumps, carburetors, etc anything that has rubber in it. Rotax only specifies the “Engine Hose Replacement”, because they are trying to limit liability for their product. The clear sight tubes for the fuel tanks, are definitely something that should be inspected every year. The plastic Tyson Tubing is very susceptible to crazing and cracking if you use Auto fuel or Mogas with alcohol in it. I definitely concur with your recommend replacing all Rubber components. With respect to Carburetors & Fuel pumps are you basically need to rebuild the carbs, or replace the fuel pump every five years.

I had a similar problem with my prior plane a Kitfox SLSA, and I was going to go flying with my wife, opened the door to be overwhelmed with the smell of fuel. I removed the seat pan to find a puddle of fuel in the bottom of the fuselage. I also once found the sight gauge was cracked and crazed and found it to be drip, drip, dripping fuel, so instead of flying, I got to drain the tanks and had to order the clear tubing so I could replace the sight gauges.
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Re: Change rubber fuel lines

Postby FredHoffman » Tue Jul 24, 2018 9:32 am

I initially had rubber Nomex covered Aeroquip Startlight fuel lines from fuel tanks to header tanks.........very bad choice. They weep vapor like crazy though them, to the point of feeling nauseous in the cockpit. I replaced them all with conductive PTFE fuel lines, smell was gone and they are replace on condition not time. I recently changed the Rotax Fuel pump too, the golden color one failed at 37 hours. Check the SB on that one, I thought it was recommend change on ULS engines or 5 years and mandatory for certified engines. I'd throw that pump in the trash quickly, some forums showed failures blocking the fuel flow to the engine rendering the electric backup pump useless. On changing the fuel pump all the engine lines were also changed to conductive PTFE, from Aircraft Specialty. Given how Stewarts Systems reacts with autogas I would make sure you have good fuel lines. I used a thread sealant used on certified aircraft at the recommendation of a AI locally, and surprise I found out it was NOT compatible with autogas. My sump drain fittings leaked and ruined some of my paint on the belly. I repainted it with a soft brush. The Stewerts paint flowed out very nicely even when brushed on, looks like the original paint. I am sure you can roll the paint on with good results from what I did to mine.

On a second build with Stewerts on an aircraft that has to use autogas I would make all holes in fabric for drains and whatever in the belly then paint the entire inside belly with ecopoly making sure to encapsulate the edges of the holes with paint, and at lowest point behind all fuel lines have holes for what ever spills to harmlessly drain out. The autogas reaction is that bad and quick!
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Re: Change rubber fuel lines

Postby danerazz » Tue Jul 24, 2018 10:17 am

Unless you run the front pickups down in front of the doors, and tie them in to the fuel system low in the plane, the front pickups will not be effective at anything other than giving an additional place to suck air into the system at worst. At best the will do nothing.

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Re: Change rubber fuel lines

Postby Tralika » Tue Jul 24, 2018 1:45 pm

The folks at Stewart's told me to use Seal-All anywhere that fuel would have a chance of getting under the top coat of paint.

I used it to seal the edge of fabric where it is cut away around the fuel caps. I also used it to seal the hole in the fabric around the header tank fuel sump.
I've also used it for a light duty adhesive.

I used low vapor fuel injection hose rather than conventional fuel hose. It's very expensive but looking at the photos Dennis posted, it looks cheap at twice the price. Be careful when shopping for this stuff. Some stores market fuel injection hose but if you read the manufacturer specs you'll see it does not meet the SAE J30R9 standard for high pressure, high temperature and resistance to ethanol and other chemical compounds. After doing some research I found it with the following part numbers.

Napa H349A
Auto Zone 50087
Orielly 27340

Those part numbers are for 5/16" ID hose. Other size hose may have different part numbers. I found it is seldom in stock and you have to hunt for it.
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Re: Change rubber fuel lines

Postby preacoupe » Tue Jul 24, 2018 5:45 pm

OK, here's the skinny. I had run a fuel line as per Rotax's recommendation back to the tanks. A bleed off line I think is their thinking. My mistake was that I had some of Aircraft Spruce's "Bing Alcohol Resistant Fuel Line", part # 05-00500. Well, it IS my own fault since this stuff I used on top of the engine coming out of the banjo fitting to my firewall. That event resulted is a leak that ran down all over the engine, motor mount, nose gear, and ultimately down the underside of the plane, resulting in stained paint....all before I even finished it.... Should not have used this stuff a second time!!! Today I discovered that that blue "sh--" actually must have become brittle and sheared off at the "T" fitting I had used to direct it back into the header. Viola! open "T" fitting draining both wing tanks into the baggage area! So, the "normal" fuel injections black hoses did work fine, but I'm going with a more professional install. Will look better and give peace of mind too. Ah, the cheap comes out expensive.

Talked with a guy at Tucson Aero today, whom I respect, and he was positive about me using the teflon lined hoses (and stainless steel braiding). Said that is what is used in certified planes. Will use everywhere...before and after firewall.

All this is the first phase. Then comes the Rotax replacements. Yes, will do everything as per Rotax's manuals. Lastly, paint on the bottom...and the header tank.

Sure wish I could come to Billy's, and see everyone, but from Tucson, that'd be some flight. I did take her to Oshkosh in '14. Round trip had my butt in the plane 47 hrs. N. Carolina would be about the same.

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Re: Change rubber fuel lines

Postby BDA » Sun Sep 16, 2018 12:37 am

I found the j30R9 hose on amazon in 3/8”

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Re: Change rubber fuel lines

Postby jjacky » Tue Sep 18, 2018 11:07 am

Thanks for all the info here people. Because of this I've converted all of my hoses to Teflon and Summit AN-6 or AN-4 fittings.
(Summit Racing® PTFE shielded AN-6 Hose SUM-220985) It actually weights less than Rubber Hose.....Thanks Again.
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