Does ethanol gas cause vacuum petcocks to fail?

Discussion in 'The Perfect Line and Other Riding Myths' started by fateddy, Apr 17, 2019.

  1. fateddy

    fateddy \m/

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    Every vacuum petcock I've had eventually started to fail. They leak and dribble and have intermittent flow. I'm wondering if constantly being bathed in 10% ethanol gas might be causing the rubber internals to break down. I just replace them with the Raptor petcock because who wants to futz with a rebuild kit for the same price.
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  2. Motor7

    Motor7 Long timer

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    I think it does, but I am a card carrying corn juice hater.
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  3. AzB

    AzB Fattest thin man

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    Yep. It ruined the fuel lines in my weed whacker, my chainsaw, trashed the vacuum petcock in my Suzuki and the float bowl gasket on the harley.
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  4. VX Rider

    VX Rider Long timer

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    NO, and please don't perpetuate the rumor it does.
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  5. 9Realms

    9Realms Drawn in by the complex plot

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    YES.

    What you've heard about ethanol in gasoline is true. Small engine repair shops love ethanol because it provides them with a steady stream of business. But if you get one of these shop owners to open up with you, he'll probably tell you he doesn't use that gasoline in his own engines or equipment. :nah
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  6. Wind_Rider

    Wind_Rider Been here awhile

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    In my experience ethanol fuel is bad in every fuel system where it is not moving frequently.

    I would also say that I have seen more problems with older fuel systems and it is my guess that the older bikes (being engineered and built before ethanol fuels were in use) used materials that cause more issues with ethanol fuel.

    If you are not riding your bikes a lot it is better to seek out non-eth fuel if you can find it where you live. I always put a tank of non ethanol fuel in my MCs before the winter months but when I am using them I put whatever fuel is convenient on the road in and as long as it gets moved through the engine quickly I have not had any problems from ethanol fuels but most of my bikes are "newer" in my current stable.
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  7. C/1/509

    C/1/509 Now with more sarcasm

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    Other Alcohol Issues
    Alcohol is corrosive and can degrade plastic, rubber or even metal parts in the fuel system that weren't engineered to use alcohol-bearing fuel. Consequently, that antique Evinrude outboard or '60s lawn tractor you bought at the swap meet might need some upgrading to stay together on today's gas. That means corrosion-resistant tanks, alcohol-tolerant rubber lines, seals and fuel-pump diaphragms, and plastic fuel-system parts that won't swell up in the presence of alcohol. Vintage boats with internal fiberglass tanks often have issues with the coating inside the tank failing, sometimes requiring massive structural modifications. Highly tuned two-stroke engines will run leaner (and consequently hotter) on the lower Btu/gallon alcohol mix, potentially leading to melted pistons and scuffed cylinder walls. Alcohol will also scour varnish and deposits out of the fuel system that have remained in place for years, which will eventually wind up in the filter or main jet, choking off the engine's fuel supply. Worse yet, the alcohol itself oxidizes in the tank and produces a tenacious brown glop that's far more damaging to fuel systems than the varnish we're used to seeing in pure petroleum fuels. In warmer weather, you can see varnish starting to form within a month of dispensing fresh fuel into a vehicle tank or storage can.
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  8. AzB

    AzB Fattest thin man

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    And that's the other issue; gasoline with ethanol has a much shorter shelf life than gas without. By the time it gets to your fuel tank, you generally have weeks before it goes bad. Gasoline without ethanol could be stored for a year or more.
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  9. foxtrapper

    foxtrapper Long timer

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    Wouldn't surprise me. Many a rubber is not fully compatible with ethanol. Fascinates me that various manufacturers of fuel system components still make and sell things not ethanol compliant.

    Vacuum petcocks always were problematic buggers though. It's a nice design idea that rarely worked so well in actual use. I'd replace it with a manual petcock myself.
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  10. Motor7

    Motor7 Long timer

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    Have you taken apart a failed carb or vac petcock that has failed using 10%? I have many times, and the damage inside is astounding. Once phase separation occurs it turns to half an half...a gooey cottage cheese sludge and a thick yellow oil. Wherever the cheese is you will find aluminium(carb/petcock) that is severely etched & where the oil is touching steel(fuel tanks) it is rusting. Even the underside of the vented gas caps rust like hell.

    I agree that modern tanks and fuel systems handle 10% ok, but damage can still be done is the stuff is left un-used and un-treated for too long. Years ago I switched to non ethanol fuel and all my carb issues in my small engines went away; chainsaws/weed whips/small genny/blowers/etc. Whenever someone brings me something that does not run my first question is what kind of fuel was left in it last and it's almost always corn juice.
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  11. jay547

    jay547 Long timer

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    Same here. Non-ethanol fuel is readily available here so we nearly always use it.
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  12. Doug Just Doug

    Doug Just Doug Silly Party Candidate Supporter

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    A few years ago I started running the canned fuel in my snow blower, lawn mower, and other small engines. Expensive, but easy, and now everything starts up right away after sitting for months.
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  13. AzB

    AzB Fattest thin man

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    Yep. It ruined the fuel lines in my weed whacker, my chainsaw, trashed the vacuum petcock in my Suzuki and the float bowl gasket on the harley.
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  14. CaptCapsize

    CaptCapsize Long timer

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    We need to encourage the save the planet types the converting food (corn) into fuel is unethical in an overpopulated starving world.
    My trick to prevent Corn fuel from going bad in the tank is to ride often enough it doesn't have time to go bad.

    The only good thing Ethanol does for fuel system is it does absorb water.

    We used to add a pint Ethanol to the Propane tanks in Hot Air Balloons to remove the water condensation. The water used to cause the old style burners to ice up, which could be bad at altitude.:grim
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  15. molochnik

    molochnik Desperately wants the blue pill

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    I held back from participating because I too have only anecdotal evidence. When I used a lot of avgas (and yes, jetting was altered to suit), I found that I had zero issues with fuel-related headaches. I had a Harley sit for almost a year with a tank of avgas in it and it fired up fine and had no leaks.
    The shiddy pump gas we have here in CA seems to destroy anything that doesn't see regular use. I'm not even sure where I could find actual gasoline around here.
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  16. PeterTrocewicz

    PeterTrocewicz Been here awhile

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    At one point I was working at a powersports dealer that sold motorcycles, ATVs and Ski-Doo snowmobiles. Ski-Doo had just brought out their fuel injection system on the 2-stroke models.
    In the first year, we had to replace the fuel pump on virtually every one we sold because ethanol had dissolved the plastic internals.
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  17. High Country Herb

    High Country Herb Adventure Connoiseur

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    I spoke with the mechanics from both local shops, and both have been in the business for decades. One of them spoke of using Stabil, and how it did and didn't work. He basically said you can use those fuels, but they will cause problems if not used immediately.

    More recently, I spoke with the other guy. He said he has paid particular attention to residues left by ethanol fuels. He said in the last few months, there has been a new residue of white powder. He guesses there is a new additive being used, or increased percentage of ethanol in fuel that has not been reported to the public. In any case, it's changed, and the timing didn't coincide with the seasonal mixture change. He said he uses the canned gasoline without ethanol that can be bought under a number of brand names. I get mine from Tractor Supply for $20/gallon, which is not feasible for motorcycles.

    I could see how a powdery residue would jam up the works in a vacuum operated petcock, but I would think they could be cleaned out. My wife's 1995 DR350 had a malfunctioning petcock when she bought it in 2013. I don't think there was nearly as much ethanol in gas back then, so I don't know if we can attribute it's failure to that.

    In any case, we got rid of that crappy petcock, and swapped it for a petcock from a raptor ATV. No problems since.

    https://procycle.us/bikepages/dr350.html#fuelsystems
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  18. Florida Lime

    Florida Lime Long timer

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    So 16 posts so far for yes, and ONE post adamant that the others are wrong. :hmmmmm

    Oh wait, 17 posts for yes - that 10% crap has messed up my small engine yard stuff as well. No problems since going to 100% gas in the mower, weedwacker, chainsaw, etc. I only use non-ethanol in the Griso (plastic tank), and the bikes kept in NC when they are going to be parked for any length of time.
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  19. VX Rider

    VX Rider Long timer

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    I dunno, I've been putting E gas in the VX for five years....I ride most every week end...sometimes skip three or four weeks....no issues.
    I guess I'm just lucky....and ride it enough to keep everything flowing?
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  20. flei

    flei cycletherapist

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    Your gov'ment says: "Ethanol causes no problems, and it will make the Corn-belt rich and save us from those A-rabs. You're gonna use it and like." Lobbying (i.e., $$$) talks.
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