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I’m working on some sort of weird engine cut out problem – only happens when I’m making a high G left turn. Anyway – I decided to replumb the fuel system (pump around) and noticed that the fuel line is no longer flexible where it has had contact with fuel and is very hard.
The old line started out bright red and flexible, but now is dull yellow and hard. It was new at the start of this season in April. Is this just bad fuel line?
Back in my R/C model days, we used silicone line for fuel that was way nastier than what my kart runs, and it never hardened up – is there a silicone based line available?
I re-did the system with some floresent orange line I had that says Franklin Motorsports on it, we’ll see if that works.
Any suggestions?
Thanks,
Gary
Gary,
What you are experiencing is typical. You should change those fuel lines when they start getting hard-usually 3-4/yr. It is part of your periodic maintenance.
Your high G cutoffs: is it bogging on turning then picks back up? Check your floats and make sure your prongs in your carb bowl are exactly horizontal with your carb body-you have to invert the carb to tell. Check both your main line fuel filter and if you have an internal filter to the carb check that also. Make sure no dirty gas.
Sounds like you run a shifter. I am specific to rotax.
hi Rich,
I’m running a shifter with a pump-around carb (no floats). It’s really wierd – midrage totally drops off as if the engine totally dies, except if you go to full throttle, then you have full power – neither will get you through a corner properly. I’m thinking that my problem is more electrical – coil wires most probably but figured I would go through the fuel system as well.
So, is there NO fule line that doesn’t harden?? I would rather pay more for that, than have to replumb the thing 3-4 times a season!
Thanks for the input!
Follow up question: Why do you need to change them if they are hard? They still flow fuel the same way whether the line is hard or soft, right? I can understand if the line is brittle and ready to break, but seriously…3 or 4 times a year for replacement?
*sigh* more spares…. (yes i know it is pretty cheap compared to some stuff)
Kirk
hi Kirk,
Actually, it seems when the line gets hard – it doesn’t seal as well – this is really important in a pump around, and critical for the pulse line. If the line is not flexible / pliable – it needs to be replaced.
am i right?
Personally, I’ve had good luck with Bing fuel line (available from any aircraft supply shop) not having had much hardening in 3 years. Tygon is quite resistant to hardening as well (I use that for the “clunker” in the tank) but typically the durometer is pretty low so avoid using it on the pulse line.
Gary,
With stiff-hard lines and the tremendous amount of vibration in a kart, hard lines crack and then……….
Tygon if it is okay with the diff gases and octane ratings we all use, then try it.
pulse line has to be flexible! no exceptions.
Hi Ken
Hi FASTGWe have the Tygon chemical resistant fuel line instock, it will not get hard unless you run Viagra in your fuel. $3/ft
“pulse line has to be flexible! no exceptions.”
Why is that Rich? I don’t think that is true. In fact the pulse single would be better through a stiff line than through a flexing line. I have even used steel braided pulse lines.
I do like the Tygon fuel line.I recieved sort of an interesting Briggs service bulletin about bulk fuel line. Seems the standard 1/4″ SAEJ30R6 fuel line can be used on any B&S engine for fuel related repairs, Except in the state of California.
“In the State of California Low-permeation hose MUST be used for fuel related repairs on B&S engines manufactured after June 30, 2005
This hose meets the most stringent emission regulations so it can be used outside California as well.”Sorry this isn’t related to shifter kart racing, yet it may be worth trying out, if you wanted cheap bulk black fuel line that will probably hold up well.
PN # 792020 1/4SAE 30R7 barrier G 1/2″ OD X 1/4″ ID.I just thought it was funny and interesting that even fuel lines are considered and tested by Briggs in an effort for them to reduce evaportive emissions. It even comes with a freshness date on the side of it.
Rush has hogged the word since his trip to the Dominican Republic
BTW (Rich Vito) the harder the line the better the intensity of the “pulse”
You don’t want your intensity reduced by a soft pipe. What would be the “efficiency” of a soft pulse? You want the medium (fuel/oil) to the carb as quickly and as much possible. Harder is better!
Are we in the gutter or what 😆 😆 😆
ANGIE!
you said this was a family web site 😳
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