So does old gas make it difficult to tune a carby? Running Opti-2 75:1

Discussion in 'General Questions' started by GoldenEagleChris, Feb 1, 2015.

  1. Hi,

    I try to ride my motorbike as much as possible to avoid the gas just sitting in the tank.

    It has been sitting for months with a full tank. (.75 g)

    I am aware that gas DOES go bad, just not sure how long it takes.

    Does the oil and gas separate like water and vinegar when stored?

    Also, I am asking this question because my carb is running like $hit.

    It seems to me that I can not get a constant tune..

    I wait to let it warm up before tuning, and I get a good tune at 1.5 turns out for the slow speed (that slotted screw in the barrel linkage) and 1.5 for the high speed setting.

    (This is not a float bowl carb that comes on the center mount China engine setup a lot of people on this site runs.)

    But then it cools down and I cant start it. I have to retune for cold.

    I ran those setting on that carb since i built the bike and now I just cant keep a tune.
    I am thinking it may be the old gas?

    So does old gas mess make it difficult to tune a carby?

  2. professor

    professor Active Member

    It does go bad quicker in a warm climate.
    How many months?

    Why not drain it and put in fresh?
    You can always add a bit of it to your car now and then to get rid of it.
    An engine will not run on really old gas.
    Gas today is different than the stuff of decades ago when leaving it for a year was no big deal.
  3. darwin

    darwin Well-Known Member

    If you want proof just look at the inside of a red plastic gas can after E-gas has been sitting in it for 4 months or so. There will be a nasty white ring where the fuel level is. That white ring crap is what fouls up your carb. Every fall drain the bugger and the gas can. That stuff is hard to get out of the can, the crusty white ring I mean. I try to have a 3 month rule, if it sits longer than that it's drain time. Plus the can gets cleaned out with soap and hot water then rinsed thoroughly.
    Last edited: Feb 2, 2015
  4. jhammondcpa

    jhammondcpa Active Member

    Here is one thought that might solve the fuel problem! Fuel Stabilizer - front&back.jpg
  5. V 35

    V 35 Member

    Fuel Stabilizer is a must ! The Alcohol in today's gas turns to water, which is the opposite of fuel .
  6. Arty

    Arty Active Member

    You bet it causes trouble. I was told the shelf life of gas these days is 30 days.
    I highly recommend "Fitch Fuel Stabilizer" for long term storage of my gas. It is not a liquid, but rather a non-sacrificial catalyst that comes in pellet form. You just throw the pellets into your gas tank and leave them there indefinitely.
    I have stored gas in a 5 gal. can for over 5 months with no seeming ill effects. When you take the top off the can, you will know if the gas is off by the stink - it's obvious.
  7. zippinaround

    zippinaround Active Member

    i usually mix mine by the litre , if i dont use the bike for 2weeks the fuel is gone off i think the poor life is down to these specific tanks in that the cap allows petrol to evaporate easier