While all of the above suggestions are certainly valid and effective, I go a slightly different route:

Non-ethanol gas is somewhat available here if you're willing to travel to get it and pay a ridiculous premium for it. I'm not willing to do either.

So I run pump 10% ethanol regular 87 octane in everything. The key for me is using GOOD synthetic 2 stroke oil. I run OPTI II at the recommended mix and just leave it when I hang the weedwhacker up for the Winter. Also leave it in all my saws.

Never had anything fail to start right up in the Spring (or mid-Winter for a saw) and no problems with fuel lines or primer bulbs turning to snot.

quote:

Originally posted by cparktd:
Sta-Bil, never an issue ever. Both 2 and 4 strokes get it.

Same here. Ounce or so of Stabil and no worries for springtime.

I've had just as many problems (if not more) when running my tanks dry as when leaving fuel in the tank (rec gas with a good synthetic 2 stroke oil).

Now I just make sure the tank is full to prevent condensation and clean up the other parts of the equipment (wash/oil everything else). Been working well.

I use 100LL Avgas from my local small airport with quality 2 stroke oil that includes a stabilizing additive.
Several of my tools sit for 6 months or more and no problems.
The Avgas usually costs less than the stations that sell ethanol free gas.

Running the tank dry, and the motors out of fuel is the WORST thing you can do for a 2 stroke. The fuel/oil mixture goes through the bearings before it gets to the combustion chamber. The bearings run dry before the engine stops running and can create a lot of wear.

Best practice is to use ethanol free fuel with a good stabilizer in it. Run the engine with it to get it through the carb and everything. If possible, it doesn't hurt to start them and run them for 10 minutes, once a month if you can, or at the very least pump the primer bulb 10 times on each of them.

Stihl recommends that for longer periods of non-use:
- empty the fuel tank
- run the saw dry

I have a Stihl 310 saw that's approximately 20 years old and a Stihl 400C saw that's a couple of years old. The 310 is on its 4th bar, 3rd carb, 2nd clutch assembly, with 7 chains in rotation. Fuel lines and oiling gear have been replaced. The shop said on its recent service that cylinder leak down is just a couple percent -- they said I would be tired of the saw long before it needs replacing. If the 310 were to go tits up tomorrow, I'd replace it with a Stihl 261CM. I'm still toying with adding a Stihl 500i saw with a 28" bar for our biggest trees, but just don't want to drop the cash.

The shop told me the 310's carb replacements were due to using automotive gas with ethanol, and letting gas sit in the saw after use. After the 2nd carb replacement, I started using pure automotive gas. The 310 ran more reliably with the non-ethanol gas, it started better after months of non-use, and the exhaust doesn't stink as much.

In the last couple of years I've used only pre-mixed alkylate fuels. Expensive, but pretty amazing. The saws start, idle, and run at high RPMs better. The exhaust hardly smells -- I don't have a 2-cycle lingering odor in my nose for a day or two after hard saw use. The Stihl 400C has only run with alkylate fuel.

I haven't tried TruFuel. Husqvarna pre-mix fuel was OK with the 400C, but the 310 experienced idling problems with it. VP pre-mix was pretty good. Stihl MotoMix has been the best so far -- idles the best, starts easily, good high-end revs. For weekend work at the family ranch, I'm currently consuming 2-3 gallons of fuel per month for the saws. That means an average of 3 tanks of fuel per day.

Whenever possible at the end of the day, I run my saws dry. I definitely run them dry if I expect non-use for a few months.