The more air the fuelp interacts with the faster it will go bad. A lot of this has to do with the humidity in the air. Your rate of volatility loss will depend on evaporation, water absorption and oxidation.

Keeping your tank full will go a loooooooong way in preventing this process since there is liitle air interacting with the fuel. In float bowls there is quite a bit (as a ratio of fuel/air) and it goes bad quickly. I can even smell he difference after working on numerous small engines. The gas just smells weird when sitting a while.

The other problem you then have to address is not the tank, but the carbs and system also containing unburnt fuel. It can degrade quicker. This can be addressed by adding stabilizer to the fuel and make sure you run the engine long enough to get it in the engine as well.

An ounce of prevention is worth a pound of cure!

 

I just ordered both fuel stabilizers from Eastwood. Daily driver and storage (up to 12 months). They seem focused on the ethanol problem, along with normal oxidation problems. About $8 a bottle, worth a try. I'll let you guys know.

http://search.eastwood.com/search?w=...custom&x=6&y=6

 

When I had my boat I was told by most boat owners to use this additive in my fuel tank. It was called Startron. The main reason was the ethanol in the fuel was eating the rubber lines and disintegrating the plastic fuel tanks. Most people then replaced their fuel tanks with stainless steel ones. The Startron was safe for diesel and gasoline. I only added a capfull for every 6-8 gallons of gasoline and it was ok to use more there was no "overdosing". I wonder if this would be ok to use in my car seeing the ethanol fuel will be stored from December to at least April. With al the rubber hoses and gaskets 15 years old now maybe this would help. Any ideas?

 

I remember from my SCCA racing days, there was a VP 100 street fuel, had no ethanol. You had to buy it in 55 gallon drums though, and they will deliver it to your house. Not cool in my garage though... Anyway, if there is a Porsche "race shop" in your town, maybe they have drums of it there. I think it was like $5/gal or so... My shop is too far away, I would burn 1/4 the tank getting home!