What is this s#*t in my fuel?

Discussion in 'Mechanic and Repair' started by capetrees, May 8, 2009.

  1. capetrees

    capetrees LawnSite Member
    from ma
    Messages: 221

    For the past two years I have owned a Scag 36" walk behind with a 15hp Kawasaki. I have had to take the machine to the shop 3 times for clogged carburator issues. The same thing comes back as the cause, some kind of vasaline like gel in the bowl that gets sucked into the carb and clogs it. I've been told its from old gas but the fuel in my tanks this last time was less than one week old. What is this crap and is there something I can add to the fuel that will get rid of this stuff or prevent it from happening? FYI, the gas we have around here has up to 10% alchohol mixed into the gas. Could this be doing it?:confused:

    Also, I don't know if its related but my engine revs up and down while its idling, not a consistant rpm. Is this related? What causes it and how do I fix it?
  2. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,069

    We are all going to have to look at converting to propane. It is a clean
    fuel and just a few things to work out in my mind. One is the need to get delivery of those tanks and another is rebate for cost of installation.
  3. milike

    milike LawnSite Member
    from MI
    Messages: 169

    you don't put vaseline in your tank do you?:hammerhead:

    evedn though it's petroleum based, it is not rated for IC engines.;)
  4. tenndigger

    tenndigger LawnSite Member
    Messages: 54

    The only thing I can think of is possibly the 10% ethanol gas is eating away the inside of your gas tank. Is it plastic or metal. If metal it could be eating away the coating inside.
    I would replace the fuel line and put an inline gas filter between the tank and carb . I try to not use ethanol blended fuels in any small engines. Suppposedly the ethanol will deteriorate older rubber lines and some plastics. I have begun to use SeaFoam additive to fuel in all small engines tanks. A gallon of SeaFoam is $50 at the parts store. Many small engine mechanics recommend it.
  5. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,027

    It could be a glycol substance and it shows up with old fuel. It is a chemical reaction that happens with fuel as it ages. Yes, Sea Foam is an additive that people use. Additives are the problem to begin with. Why add more?
  6. capetrees

    capetrees LawnSite Member
    from ma
    Messages: 221

    There already is an inline fuel filter on the machine and the tank is a factory plastic tank. I can't imagine the tank being degraded by gasoline. Millions of gas tanks are made of plastic.

    I have heard of this Seafoam for marine engines. Someone actually showed it to me yesterday for the first time. My guess from reading the label is that it is a petroleum/alchohol additive used to "cure all your problems". As mentioned, why add additives to something that has an additive, the 10% alchohol? I think the gel that is showing up is possibly a small amout of water mixing with the alchohol but I can't think of how that is happening on the chemical level. Alchohol is supposed to disolve water or at least dissipate it so it burns along with the gas, thus Drygas.

  7. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,027

    My post isn't a theory, feeling, guess, conjecture or perceived experience. It is from tests run by an small engine manufacturer. And none recommend a fuel additive. Alcohol doesn't dissolve water, it absorbs it, that's part of the chemical reaction part
    Last edited: May 9, 2009
  8. Breezmeister

    Breezmeister LawnSite Bronze Member
    Male, from South Jersey
    Messages: 1,717

    What I would suggest is get a better fuel filter. Ask your dealer for a lower micron filter or go on line and check out the different fuel filters.

    As for the stuff in the fuel, I had a problem a few years back where I got gas from the bottom of a in ground tank, from all the crap that is in fuel. As the gas starts to break down, will settle to the bottom of the tank and if the tank is near empty, you are going to get that crap in your fuel. Fine out when the tank was filled, if its more then a week, go some place else, or go to a gas station that has a lot of use. When new fuel is added to a in ground tank, all the stuff is mixed back into the fuel.........
    ericg likes this.
  9. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Get your fuel from another gas station, see if that fixes it.
  10. wallzwallz

    wallzwallz LawnSite Senior Member
    Messages: 361

    I'm in MA also and since they added the alcohol have had similiar problems in equipment. My old Gravelys have the most problems, I think the alcohol pushes all the crap through and don't know why it gels.

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