Carb flooding because of sticking float needles coated with film of dissolved fuel line from alcohol

johnm said:
I have found that allowing ethanol fuel to dry out in your carb is a recipe for all sorts of problems. Even if fuel lines don't dissolve.

I left my new Premiers for 6 months without draining them and had:

- green powder aĺl through the small passages

- a yellow golden hard film all over the internal carb surfaces

- a corrosion ring all around the main needle. I had to replace them because it did not polished out and you could feel it with a finger nail.

This is using NZ 95 pump gas which is reportedly 5 % ethanol but AA testing has shown a much wider range of ethanol content than that.

Letting the bike run dry after turning the fuel off is a good idea for semi regular bike use.
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What gas do you use? Years ago when I looked into it, I thought Z (used to be Shell) was e-free?
 
Looks like the situation is changing all the time. Mobil 98 and Gull force 10 both have 10 % ethanol.

I couldn't find the AA report but looks like the different brands have MDS which give the blend compositions. I couldn't find any 95 gas that had ethanol mentioned. I think they boost the octane with light ends which are not that stable and probably go in a month or two in an unsealed tank.

NPD 100 plus looks interesting. But very few stations except around Christchurch and Nelson.

Waikato say they get their gas from Mobil and 91 and 95 have no ethanol.

It's strange because a few years back they were using ethanol but not at present it seems.
 
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Tygon LP-1100 may be the answer for clear (transparant yellow) fuel line for ethanol based fuel. Its claimed to be rated for up to 100% ethanol. But I haven't tested it yet.

specs and data sheet here:
www.processsystems.saint-gobain.com

Tygon® LP-1100

Flexible Fuel Tubing
www.processsystems.saint-gobain.com www.processsystems.saint-gobain.com
 
after using UK ethanol fuel for several years, with big gaps in usage, I took off the float bowl recently and couldn’t see any sign of deposits anywhere. Looked like new.
 
When I worked in the semi conductor / wafer manufacturing industry we used to use all sorts of exotic and dangerous chemicals typically in their highest concentrations.

All these wonderful and extremely scary liquids would be " pumped " through Teflon ( PTFE ) tubing, they never degraded even over years of use.

One of these scary chemicals was Hydrofluoric Acid @ 75% conc - this stuff even dissolves human bones after passing through the skin !

What is my point ??? teflon pipe is RESISTANT to pretty much everything.

I have in fact used PTFE pipe on my 1955 Land Rover now for over 12 years without issue whilst others ( until they did the same ) suffered rotting fuel lines due to ethanol.


Sceptical ??? Take a look at this link for chemical resistance and scroll through all the substances it copes with, even petrolium spirits
:tiphat:


http://www.componentsupplycompany.com/ptfe-chemical-resistance-data.php
 
With alcohol, it attracts moisture which can react with the zinc in the aluminium of the carbs and create a white oxide inside their fuel bowls. I think Mikuni carbs have more zinc in their alloys than Amals.
 
1/4" clear Tygon LP-1100 is hard to find in small quantities. It may be formulated for ethanol but it is layed with an inner liner. Last time I tried a layered clear alk proof line the inner liner separated when jamming onto a barb - no good. So the special Tygon LP-1100 line is questionable until tested. Looks like it might be back to black Viton.
 
Like I said earlier, no trouble in 15 years now - all on ethanol/gas - with the clear fuel line that Old Britts carried...WHATEVER it was. ;)
 
I can't get ethanol free and often have to use E10. My transparent lines quite quickly became stiff and were yellowing, so I replaced them with ethanol proof line supplied by Amal, from their website. It's black. They also do better looking braided lines, but I didn't have the knowhow for the fittings on those. See: https://amalcarb.co.uk/fuelling-accessories/fuel-hose.html

I'm now in the habit of turning the taps off before home, to run the bowl dry. Don't know if that will actually reduce the opportunity for corrosion of the carb body? All seems fine for the last 4,000 miles doing this.
 
FWIW, the clear lines always turned yellow/brownish and stiffened even back in the old days long before ethanol-in-gas was invented so I don't think the ethanol has anything to do with that.
 
MexicoMike said:
FWIW, the clear lines always turned yellow/brownish and stiffened even back in the old days long before ethanol-in-gas was invented so I don't think the ethanol has anything to do with that.
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It happened quickly, less than 6 months. I assumed, perhaps wrongly, I'd be better off switching them out.
 
The clear PVC lines may have worked for some but they didn't for me. The Yellowish Tygon F-4040-A may be OK or not - some companies don't recommend it for ethanol based gas. The black viton is cleared for ethanol. Samples of all three are going into an air tight jar with ethanol laced gas for a month and will be inspected under a microspope.

Here's what happened to clear Tygon C-210-A after soaking in ethanol laced gas for a week. You can see it turning yellow and swelling up. It also went soft and is easily punctured or damaged compared to un-soaked Tygon.

Carb flooding because of sticking float needles coated with film of dissolved fuel line from alcohol
 
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concours said:
This is all I will use. Stays pliable. Pulls easily off barb fittings. No clamps needed. No leaks.

MP Premium Fuel Line, Gray 1/4" ID X 3' - Motion Pro

Motion Pro - High quality cables, tools and controls for motorcycles, ATVs, snowmobiles and personal watercraft.
www.motionpro.com www.motionpro.com



Motion Pro Premium Fuel Line - Motion Pro

Motion Pro - High quality cables, tools and controls for motorcycles, ATVs, snowmobiles and personal watercraft.
www.motionpro.com www.motionpro.com
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FYI, the motionpro IS Tygon, and, "seeing the fuel flow" is not needed on carbs with a tickler, you know in 3 seconds if there is fuel....
 
jseng1 said:
1/4" clear Tygon LP-1100 is hard to find in small quantities. It may be formulated for ethanol but it is layed with an inner liner. Last time I tried a layered clear alk proof line the inner liner separated when jamming onto a barb - no good. So the special Tygon LP-1100 line is questionable until tested. Looks like it might be back to black Viton.
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www.aircraftspruce.com

Tygon Lp-1200 Fuel Line Tubing | Aircraft Spruce

Tygon Lp-1200 Fuel Line Tubing Clear, high-performance fuel tubing for small engines.
www.aircraftspruce.com www.aircraftspruce.com

Available by the foot.

Readily available. Great people to deal with.
 
Quote from Aircraft Spruce.
"Fuel Line SHOULD ALWAYS BE INSPECTED CAREFULLY BEFORE EACH FLIGHT and REPLACED EVERY YEAR. Fuel line can be damaged by UV rays and coastal environments."
 
For years I marveled at the pliability of fuel line on Jap bikes, after ten tears it was still easy to work with, sealed tight. I noticed it was two different layers.
That is what the MotionPro is like.
 
concours said:
www.aircraftspruce.com

Tygon Lp-1200 Fuel Line Tubing | Aircraft Spruce

Tygon Lp-1200 Fuel Line Tubing Clear, high-performance fuel tubing for small engines.
www.aircraftspruce.com www.aircraftspruce.com

Available by the foot.

Readily available. Great people to deal with.
Click to expand...
This is dual layer fuel line. Yes its alk proof. But the dual layer can be a problem. However - aircraft spruce offers Rotax fuel line that looks interesting. Alk resistant and I bet it the same as Tygon F-4040-A which maybe OK if it passes the soak in enthanol laced gas for a month test.

www.aircraftspruce.com

Bing Alcohol Resistant Fuel Line | Aircraft Spruce

Bing Alcohol Resistant Fuel Line This fuel line is blue in color and does not rot or deteriorate from the inside, clogging the carburetor or fuel system. It withstands 50 PSI and tensile strength is 8000 PSI. It is resistant to tempe...
www.aircraftspruce.com www.aircraftspruce.com
 
I got some yellow Tygon 4040 in and soaked it in ethanol laced gas overnight (soaked image on right side). It did soften a bit, absorb some alk and swell a little but otherwise it seems OK. No deterioration of the Tygon so far. Soaking for a month may show a problem or not.

Carb flooding because of sticking float needles coated with film of dissolved fuel line from alcohol
 
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