Fuel quality....
I believe, based on what our customers have been bringing us, that ethanol is not the big blame for quickly staled fuel, as everyone seems to think. Many, many times over the last few years I've heard that "I've been using non-ethanol fuel, so why does this happen?"......probably 10 times a week being conservative.
The fuel we have evaporates, and quickly. What I want everyone to do, and do this cautiously, is to grab a quart jar and put about 1/2 quart of gasoline into it. Doesn't matter if it's cheap low octane or premium, though the good stuff happens quicker. Anyway, put the jar outside and uncovered for a few hours. Mark where your original fuel level is and after a few hours, see how much the fuel level drops. The warmer the air, the more you'll be surprised. I did this last summer and within ONE HOUR, the half filled jar of fuel had evaporated 1/2 of it's contents. During the evaporation process, the fuel became cold. And of course where I live it's humid, so as it cooled it drew moisture in. What was left after 4 hours was about an ounce of water and about 3/4 cup of what I call fuel, although it smelled NOTHING like the original gasoline that I put into the jar. That is the stuff that ends up in your carburetor and fuel system. Similar to salt water. It evaporates and leaves the salt behind. A carburetor is more sensitive to this because the carb is vented to the atmosphere. It has to be in order for it to work as designed. EFI systems don't have a vented carb. The tanks are all vented of course.
The jar test tells me that ethanol is not solely to blame. Yes E10 does not agree with fuel lines in older equipment. Yes it's subject to phase separation. But Kubota (and most other) equipment has been designed from the get-go for over 10 years now, to run and run properly on E10 fuel.
The best cure is prevention. Either don't let it sit, or don't leave it full of fuel, but if you run it out, run it ALL out, and drain the bowl. When the engine dies-even on the Kohler's-there is still some fuel left in the carb bowl, lines, pump, and tank. Or use the equipment often.
If you've fallen victim to letting it sit, pouring good fresh fuel in, on top of the junk that's already in the system, does nothing but waste money if you have to do a fuel system flush and clean.
Sta-bil doesn't really work as well as it says it does, based on what our customers bring us/tell us. Might prolong the inevitable for a couple weeks but it doesn't cure it.
And finally no fuel treatment that I have tested (a ton of them) will "fix" bad fuel, not a single one. And none of them will "fix" moisture in fuel either. I had a sales guy stop in the shop once and tried to sell me some of his snake oil, I think he called Phaser or something like that. Said it'd remove moisture from the gasoline, and even poured some gas into a glass jar, added water, and then poured in his Phaser product. The water dispersed, more or less disappeared. But it was still in there, and that was my argument. About an hour after the guy left, the water fell right back to the bottom of the jar. Glad we didn't waste any money on that stuff.
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