Several 2 stroke oils come with a stabilizer for the fuel. They had to out of self-preservation ( no pun intended ). Not sure about Ams.
About 18 years ago the "mixers" at the blending stations were ordered to change the formula of gasoline, effectively removing any stabilizers that were in it. I should say that I only know this happened at the plant close to me, but I'm guessing the formula was changed universally, given that gas doesn't have much of a storage life anymore.
Why would they do this? The reason I heard from the chemist was simply that it "wasn't needed anymore"..... that it was part of an old formula.
Well, that's probably true for cars, but for small engines that frequently get put away with gas still in the tank, that created a huge problem. Gas that gets left too long these days turns to varnish ( for lack of a better term ). It melts fuel lines, plugs fuel nozzles, plugs fuel filters, etc.
As far as your 100-1 ratio....geez, I never like to hear that kind of thing because you're living right on the edge of wetness by doing that. You have zero margin of error when using such a lean mixture. The question I would ask you is...why do that? All you have to do is have your high speed fuel nozzle get a tiny bit plugged, and it won't take long to score your engine. Or run it on a hot day, same result. Back it off to 50-1 and now you've given yourself some cushion for failure, that's my recommendation. 30 years of working on 2 cycles has taught me that much....
To store your equipment for the Winter, dump all the fuel out of the tank, and then start the machine and keep working the choke back and forth until it won't run anymore. Then leave the gas cap off until the remaining fuel evaporates from the tank.
Hope this helps...
