If in doubt, test it...
Pump a small amount of fuel from the tank (or better yet, from the carb float bowl into a small glass jar.
Let sit 10-15 minutes...smell it (it should smell like gas). look at it (water/gel will sink to the bottom, this is not good).
Dip a nail (that carpenters use to build buildings) or similar object into the bottom of the glass jar, remove and light with a bic lighter.
If the fuel on the nail lights and burns...good fuel, if not, bad fuel and dispose.
