I realize this isn't a car question. There doesn't seem to be an appropriate Exchange for it, so I'm trying it here.
I have a two-stroke engine (for a rototiller), and it worked more-or-less well enough until it rained. It seems as if there might be water in the fuel. I tried filtering it with a brand new fuel filter specifically for removing water. Then I tried adding isopropyl alcohol, and some octane booster (as suggested elsewhere on the Internets). No luck.
It starts -- but won't keep running for more than a second -- if I put starter fluid in the choke with the air filter off.
I'm not sure what else to do. Any suggestions would be accepted with gratitude.