We are having a real problem finding fuel here in St. Louis, and in anticipating that someday I may have this problem, I always bought some fuel whenever I went to SIG for their C/L contest, or to Montezuma for any reason. I had quite a big stash, and some of it was stuff from 2012 or older. Like a lot of people, I have some that was of questionable quality and on the 'weed killer" shelf. Just to be able to sport fly, I have been going through everything I have to see what runs and what won't and using it in my fun flying airplanes. I have not had any problems so far and I have burned through quite a bit of it and some I know had to be 20 years old or so. I have opened up 40 year old cans of Cox fuel before and had it run just fine in Cox engines. If it's been stored in a stable atmosphere and out of the sunlight, it ought to run, and the thing to do is try it in a couple of different engines and plugs. If it won't run in anything, then it really is weed killer! I had some Fox brand fuel stashed also, so you know how old that must be!. Two gallons of a 22% total oil, half and half mix that I got in some stuff I bought. It almost looked like straight Klotz oil! I have had plenty of SIG fuel to run over the years so just let it sit. I went through my entire stock last week and sorted things out and found some Fox Dukes Fuel, which was 10% nitro and 20% all castor. I had two gallons of each, so mixed up a gallon using half a gallon of each, and I'l be damned if it doesn't run pretty nice. Comparing it to a gallon of the freshest SIG Champion I have and it runs about the same. So I'm using it to fun fly and saving the good stuff for any contest work, but not much of that in my future. So once you get some reliable electric igniter systems working and some other plugs to try, might as well try some of your other fuel. You might be surprise what will still operate. it won't be Gold Bond Certified, but good enough for testing. Good luck with it.
Type at you later,
Dan McEntee