Remember when a good dose of "HEET" took care of bad (wet) gas or overall condensation in the winter back in the 60's, 70's and 80's?

I have had no issues since switching to name brand gas for the tractors/small engines and pulled a tank off a D-Series recently to find it was slick as a whistle, a tank on a tractor I bought that had sat for yearsand it was not so pretty when I brought it home. 

Many "bowl cleanings" later and quite a few screen change outs and it looks pretty nice but it has been used regularly.

My carb rebuilder gave me some sage advise, if it's gonna sit for awhile, fill it full enough that a quart of MM Oil can be added to fill it right to the top as a top-off.

Run it for a while so the MM get's mixed in plus the residue coats the empty portion at the top to protect the tank metal while in storage.

Had one I treated like that sat nearly a year to the day and it fired right off and ran fine.

We are pretty darn dry here with low humidity and I think where you live does play into fuel issues.

I'd say it's just fine.  I pulled the carb apart on my WC that has had E10 in it from day one of a 20 year old rebuild.  It looked as clean inside as it did the day I did the work 20 years ago.  Everything I own has E10 in it and everything will start and run just fine on gas that has been in the tank for months.

AaronSEIA

winters.

 

We would never go back to regular with 10% ethanol.

The issue with ethanol, is partly what it is, and partly what it does.

Ethanol is a Hygroscopic, Miscable, Versatile solvent.  This means it absorbs moisture, (and the water it absorbs does NOT need to be in a liquid state)  it will do it in any proportion, and it will mix with a variety of many other things as well.

In a garage-test, a sample of ethanol, left in a cloth-covered mason jar in a midwestern garage will increase it's MASS simply by extracting it from the air... and you'll SEE it do it, given an appropriate amount of time for your local environment, but you'll need a SCALE to accurately MEASURE it... because when you add one cup of ethanol to one cup water, you end up with SLIGHTLY LESS THAN two cups of VOLUME... but the concordant weights match.

As POLAR compound... it readily gathers ionic compounds and organic solvents like acetic acid, ethylene glycol, chloroform, hexane, and trichloroethane.... and many others.

Ethanol cannot be transported via pipeline like petroleum products-  once it is exposed to moisture, it absorbs it, and any contaminants (particularly those listed above), it inherits the circumstances of the contaminants.  Acetic acid being a big one- white metals, particularly castings, where dissimilar metals exist) react in a galvanic corrosion process.  This is frequently misinterpreted as 'cleaning', as acetic acid (absorbed from the air, with moisture) etches the inside of fuel systems and breaks down polymers (rubber and plastics).

In an anhydrous state (meaning, no water absorbed) It's flashpoint is 57.2 degrees F  (for comparison, gasoline is -45F).  This changes once it's absorbed other compounds, and as such, it is very difficult to obtain an optimal combustion mixture.

While it's touted as a large reducer of emmissions, this is only the case when complete combustion occurs- When incomplete combustion occurs, ethanol yields significantly larger amounts of 'bad stuff' (formaldehyde and acetaldehyde).

As Tim noted, the humidity of an individual's area DOES impact degradation of motor fuel... but the impact that moisture ingress has can be decieving.  A vented steel fuel tank feeding a steel fuel line to a cast iron carb with a brass float is NOT the same as a controlled-vented plastic tank with stainless lines, in-tank fuel pump, steel injectors with ceramic nozzles.

If a fuel system is clean, perfectly sealed, and absolutely no way for any contaminants to conjoin with ethanol-blend systems, there is no way for it to cause problems.

The reality is, that there is no way to maintain a clean, perfectly sealed system... EVER.  It WILL wind up with contaminants, and those contaminants, once in combination with others, result in reactions that cause damage.  Because of this simple fact, and ethanol's hygroscopic nature, the worst thing anyone could ever do to ANY fuel system, is leave it sitting. 

Straight gasoline won't attract really bad stuff.  What it WILL do... is evaporate... and it will ALWAYS evaporate the lightest-fractions-first... as time goes by, the lighter ones leave, and the heavier ones stay behind... leaving thick gooey sludge... in much the same way a refinery separates greases and bunker oils from kerosenes and gasoline.

Fortunately, for those of you that have tractors running Propane...  as long as the filters catch any dirt, and the regulators don't get stuck from sitting (spring fatigue, etc), they'll be good basically eternally, because it IS a sealed system... it is very, very hard to contaminate.

For gasoline engines, regardless of WHAT you put in the tank, shutting off the fuel valve and running the carb dry, and/or opening the carb drain to run it dry, will ALWAYS offer chances for better result.  Filling the tank to ALMOST the top is also a good idea, as it eliminates volume for air to occupy, but be careful- as temperature changes, the fuel must be able to expand and contract... add too much, and the system will generate pressure and leak out somewhere, usually in a very undesireable way.

I just had my tank cleaned and lined. Filled it up and have run about half of the gas through the tractor. I took the sediment bowl off and have not yet replaced it. I added a filter down line of the shut-off. I have went through four filters, counting the newest. The crud that came out prior to the tank rework was goopie and nasty. The new filter is clean and clear.

I plan on putting in a new sediment bowl to complement the filter, but that's down the road a bit.

I believe in Sea Foam, too. I don't run 10% in the tractor, I have what I believe to be a good source for gas. I don't buy gas from the 7-11 style stations. I have been told that 10% is fine as long as it is used. Letting it sit, especially in small equipment, is where the problems begin. I can verify that to be true, for me at least.

IMO, if you started using SEA FOAM as a "conditioner", you wouldn't need to spring for "premium"