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GrampaR123's avatar
GrampaR123
Explorer
Jan 31, 2020

RV gasoline life span in long term storage

Due to health problems our motorhome has been stored unused for over a year. How long does gasoline last before it goes bad?
  • I had fuel injected vehicle sit for 2 years with no obvious problem. I rotate emergency gas stores on a yearly basis - no problems.
  • jdc1 wrote:
    You'll be fine. How long do those unwanted new cars on the lot sit before they drop the price in half?


    How much gas do you think new cars have in them?


    fitznj wrote:
    I had a classic car that did not get driven too often (<150/year); it
    had at least 2 year old gas in the tank and drove ok each time.

    However - it sat unused for more than couple of years and the float bowl
    and jets had a chalky residue which had to be cleaned out.

    If you can; run the engine to operating - every once in a while and maybe
    add fresh gas with seafoam.


    My old cars I would normally put fresh gas in them every time I used it. Never fill, but enough to go and back.
    I also put a valve in the fuel lines so I could shut off gas, and run the carb dry.
    But I'm not sure that modern fuel systems are not more sensitive to old gas, or that the modern blends of gas keep that well.
    The pickup I have now I make a point to drive some every week. When the gauge reads 1/4, I put in 5 gallons. Before I hook up to trailer, I fill the tank so over half is fresh. If it has been couple of months without using the trailer, I notice a decrease in mileage the first tank. Run down to 1/4, refill a couple times, better.
  • valhalla360 wrote:
    How much fuel is in the tank?

    If it's on "E", consider draining and disposing of the old fuel if you can get at the outlet easily.

    Otherwise, you can dilute with fresh gas.

    On the positive side, if it's a full tank of gas, you are less likely to get water in the fuel but be prepared to swap out filters if there is water in there.

    Unless it's a really old MH, I expect it has fuel injection so the float bowl and carb jets gunking up are likely not an issue.


    Might be worthwhile to siphon the level down to half or less, (lower is better) before you fill with fresh. If what you take out does not smell to bad mix with fresh in car that you can drive, but do not expect to demand peak performance.
  • Siphon it out, 5 gallons at a time. Put it in your car and use it up. Refill with fresh fuel and run it out about 100 miles. That will use up any old fuel. Don't overthink it.....Dennis
  • Depends on the definition of "long term". My Allegro sat for 6 years in a tow yard with 80 gallons of gas in it. The guy that sold it to me said they added Stabil to it. I didn't want to run it through my new engine (the reason it was in a tow yard) so I siphoned it out 5 gallons at a time and burned it in my daily drivers. They ran fine with it.

    The Allegro sits more than it's driven (like a lot of RVs). The gas I have in it now is almost a year old. I run it once a month and it's fine - always starts right up. I fill it with fresh fuel at the beginning of every season (late-Spring, early-Summer).