In a vented system this new fuel doesn't do well sitting for long periods of time.
When I'm done with any piece of power equipment, chainsaw, string trimmer, generator, etc I get them running, dump the tank, and continue to run them till the carb goes empty. Been doing this now for at least 15 years and have zero issues with any of my stuff.
I would never put Seafoam or any other stabilizers or additives in the fuel right to start with, nor would I rely on them to keep the water out of the fuel or to keep it from loosing octane, etc.
For the saws that I use frequently, or anything that I don't let sit for months and years I don't run them empty. Instead I clean them up, sharpen the chain, and fill the fuel and oil tanks so they are ready to go for the next outing.
The three biggest problems I see with this new fuel (and I work on fuel systems, carburetors and small equipment for a living) is that the fuel brings in considerable moisture/water with it, at least 1 to 1 with the amount of ethanol content. If left sitting it tends to form what we call "apple jelly" in the tanks and it will find it's way into the carb and plug things up. The second problem is simply loosing octane. For some reason this new fuel in a vented system starts loosing it octane quickly. I wouldn't run any of it that's been around more than about 6 months, and it may give you issues in about half that amount of time. The third issue is swelling up any type of rubber, so carb kits, fuel lines and anything else that comes in contact with this new fuel can not be rubber based. Some companies use nitrile, others use various grades of flouroelostomer (Viton) to make fuel lines and carburetor parts to survive in modern fuel blends.
Case in point, guy drops off a Honda 3000 watt portable generator recently. He says no-start. He also says that he put Stabil in the fuel before putting it away some 8-10 years ago. So I figure the carb is all plugged up, but it's clean. It has spark, has fuel in the carb, fuel getting to the plug but woln't start or even attempt to start.
I dump all the fuel, replace it with fresh fuel, give the intake to the carb a quit squirt of fresh gas and it roars to life instantly and runs sort of OK.
Then I tried to light the fuel removed from the tank in the gravel driveway outside the shop and had trouble lighting it! Not only was it difficult to ignite it burned more like kerosene that gasoline.
I noticed the generator was "hunting" pretty heavy and told the owner about it. He said it's always done that but fine under load. So I hook two 1500 watt heaters to it and it stops hunting, but will only pull 80 something volts. I "tipped-in" the choke flap to richen things up and it comes right up to 115 volts and smooths right out. I ended up taking out the main jet and increasing the metering area by .003". It no longer hunts at all and pulls full load w/o any issues.
I find myself doing this a lot with older equipment that was originally sold before they started putting ethanol in the fuel and "reformulating" the gas, oxygenated, etc. It takes about 5-7 percent more of this new fuel to effectively get the job done vs older fuel blends. Just a little extra info that may help some folks who read these threads......Cliff
