My last race was in november.

Have about 4 gal left in my 10 gal fuel cel.

Should I add fuel stabilizer? Probably won't run again until April.

Also, will the stabilizer damage the fuel cel foam or bladder?

thanks,
dr

if the information on the StaBil label is to be believed, the horse has left the barn.

drain it and use it in your lawnmower.

then, either leave it empty or refill with fresh gas - and StaBil.
no experience on foam or bladder damage, but i don't see how the product could damage either.
hopefully someone with actual firsthand experience will chime in - or i bet there's a contact information number or website on the product - you might check with the manufactorer...

(i bought a bottle of StaBil in the autumn but i have been able to drive the car more than i expected - i haven't used it. they also make a cylinder fogging spray that might be of interest, especially in a warm, moist environment...)

Gasloine is blended from low octane straight run gas and high octane reformed or cracked gasoline (modified molecular structure).

The reformed refining process not only modifies the molecules, it optomizes ring type molecules, i think they call them aromatics. They are inherently unstable over time and break down into less desirable chain type molecules.

Gasoline has vapor pressure (a measurement of the tendency to evaporate). Gas sold in the summer has a lower vapor point than gas sold in the winter because the hotter temperatures of summer would promote more evaporation.
Over time the light ends of the gas (hydrogen, iso butane, etc.) will evaporate and leave the gas with lower octane ratings and higher concentrations of parafins and varnishes. That, and the break down of the aromatics is what makes the gasoline smell bad.

The breakdown of gasoline is dependant on a few things. Whether the gas is high RVP or low, the temperature and hunidity of where it is being stored, and how well it is sealed from the atmosphere, and the level of the tank. Normally you can count on a loss of around 2 octane points in the first month, then 1 per month after that if it is high RVP stored in a warm or hot environment.

To make gas last longer, use sta-bil. AFAIK it has no negative effects.
Otherwise, try to keep the gas stored in a cool dry place, keep the tank as full as possible (reduces the rate of evaporation), and keep it sealed as well as possible and reasonable. It has to breathe, but don't leave the cap off if you know what I mean.

Much will depend on the type of fuel used. Racing type ? or pump gas? The fuel cell manufacturer can or should be able to advise of the effect on stored fuel to the dampning material in the tank. Pump gas out here begins to degrade after about 20 days according to our field engineers.

To make a long story short
It won't hurt anything
It works great in all types of engines
I've been using it for years
I used to have to take apart some of my small engines and clean the carbs every year but since I 've been using Stabil I don't have to.
That gets critical on $5k snowmobile engines.

If you are racing the car....make sure it won't disqualify you for the event if the fuel has been tampered with. I don't know what your rules are.

Good point. Drain it. If you are running SCCA you already have a dump port after the pump for fuel testing. Pump it out.


B

Well, I'm "supposed to have a fuel port" but I don't.

The vintage class down here is pretty laid back.

Thanks for the info guys, I didn't realize the gas degraded that fast. I will drain the cel for now.

dr