Last edited by jrevens; 01-19-2017 at 11:44 AM. Reason: Corrected spelling
John Evens
Arvada, CO
Kitfox SS7 N27JE
EAA Lifetime
Chap. 43 honorary Lifetime
I learned that lesson along the way too John....the fuel injection clamps work great on...well....fuel hose!
Drips do not seem to be a problem on fuel lines even if there is no "constant pressure" feature...I would speculate that has to do with two things...the materials used for fuel line connections being less succeptable to cold shrink; and, the fact that cold shrink is a % of scale thing with a small diameter application ending up with far less total shrink than a larger diameter application - i.e. 5% of 1" is more than 5% of 5/16".
Dave S
Kitfox 7 Trigear (Flying since 2009)
912ULS Warp Drive
St Paul, MN
I think you're exactly right, Dave. The neat thing about the high quality silicone hoses, for coolant applications, is that the cold shrink is very minimal, if any, and it remains soft & pliable at low temperatures, as well as having a very high upper temperature limit. It also has a very long life... it doesn't "age" for all practical purposes. That's the main reason I didn't use the larger, heavier constant pressure clamps on those lines. I used the Rotax supplied spring clamps for the 8 hoses on the engine itself, but on all of the 1" hoses I used the smooth lined worm screw clamps, with "relieved" edges that can't dig into the hose as easily, made by ABA. There are other similar clamps made by others... the race car guys have a good handle on this stuff.
John Evens
Arvada, CO
Kitfox SS7 N27JE
EAA Lifetime
Chap. 43 honorary Lifetime
How about ClampTite wire clamping?
SS7 O-200 Whirlwind
That ClampTite tool is an awesome field expedient way to cary clamps. Kinda pricey.
Eddie
This conversation sounds like it covers several of our hoses. I am having a seepage problem at the base of the vent line at the header tank. I have 2 threaded clamps and after decent I and smell gas. It sets over night and I get some leakage. Any solution? Why do they use the clear soft line?
Fastfred,
I don't think this is a common problem. The tubing has not been an issue by itself. I don't think this is a cold shrink deal like can happen on the larger coolant hoses.
A few things to consider:
1) Do you have the plastic header tank or aluminum one? The plastic one is more succepible to issues - such as sealing the threaded nipple that goes in the center for for the vent line.
2) Fit between the hose and the nipple - if the fit is not as close as it should be it might be hard to clamp up. Hose should fit snug on the straight part of the nipple and tightly over the barb.
3) Any cut, scratch etc on either the nipple or the inside of the hose could be a source of problems. How old is the hose?
4) The clamp should be 100% round - if there is a bend or kink in the clamp material that's a potential source.
Not sure if this helps any, but, sounds like something that might take some detail work figuring out.
Good luck.
PS - the transparent line is historical on Kitfoxes and there is some thought seeing the fuel might allow a person to realize they are running on the fuel in the header tank only if a bubble shows up coming down the vent line, although I'd like to think everyone would keep a better reserve of fuel, or at least a legal reserve .
Dave S
Kitfox 7 Trigear (Flying since 2009)
912ULS Warp Drive
St Paul, MN
It is a new aluminum tank and fittings.
The hose fit seems good and I have to cut it off to remove it every time.
All new hose.
I put a new perfect fit clamp on and a normal hose clamp. Double clamped!
I have a low fuel light installed so the clear hose is not an issue.
All these steps improved the problem but after leaving it over night it still seeped out a little.
I finally epoxied the hose and flew a couple hours yesterday . I pulled the seat and checked the paper towel I wrapped around the fitting. No seepage but on most descents I still got a fuel smell. Why is that?
Now a new problem the Tach is no longer reading correctly? My research says they do go bad and I assume it is the original 2004. I ordered a new from Spruce. So I can go to Loch Haven next week.
I saw on here where changing all the lines to fuel injection lines stops the odor in descent?
Thanks for looking at my issue .It has been frustrating and I have gotten good at pulling the seat and about $20 in zip ties.
If you just did fuel Injection hose and AN fittings in the cockpit it wouldn’t be too expensive.
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Josh Esser
Flying SS7
Rotax 914iS
AirMaster Prop
Edmonton, AB, CWL3