"Isn't there a gasoline additive you can add to the gas which will keep it 'fresh' for up to 24 months? I've seen it at Home Depot, though have never used it. I think a tube was less than $1.00."
(From: Floyd Reed (firstname.lastname@example.org).)
Being an old small engine mechanic from way back, I suggest that you don't use any additives to keep your gasoline 'fresh'. Dispose of old gasoline (end of season) by dumping it in the (nearly full) fuel tank of your car, then refill your gas can at the beginning of the mowing season. It should last you the season. With this method, you spend no extra on additives (that are no good for an engine), you don't waste 'old' gasoline, and you don't dump raw gasoline into the environment.
(From: Dan Weise (email@example.com).)
I have found the commercial product Stabil the best thing since sliced bread. It prevents the gasoline in the gas tank from gumming up. I'm too busy to run around emptying gas tanks in the fall.
Instead, I shoot in a squirt of Stabil, run the engine for 5 minutes, shut the gas valve off (unless it's a suction carb mounted on the gas tank) and the engines start next spring.
That was NOT the case before Stabil. I can't count the number of times I've disassembled a carb and sprayed Gumout trying to unclog the main jet or the idle jet. Or had the float stick down and flood everything in sight. All because of gummy gasoline.
I've used Stabil for about 10 years with great success.
I also use that Slick 50 teflon stuff, but have no idea whether it does any good or not. But for the investment in an engine, I can't see that it hurts. The intermittent duty of many engines makes them more vulnerable to oil run-off than vehicles that are used daily.