I may or may not have put fuel stabilizer in the most recent gas to go my lawn mower. I run the engine with the stabilizer in it then stow it for the winter, siphon the gas out and use it in my snow blower.

Will it hurt if I put more fuel stabilizer in gas that may already have it in it?

Unless you're living in the Rain Forest, fuel stablizer is a marketing gimmick, IMO.

Quoted: Unless you're living in the Rain Forest, fuel stablizer is a marketing gimmick, IMO.

It most certinly is not.  Bud I have no "proof" other than it works for me.

Does fuel stabilizer work ?  YES

Do I use it ?  NO

All I do is dump the fuel in the Spring and replace it with fresh stuff.

Quoted: Unless you're living in the Rain Forest, fuel stablizer is a marketing gimmick, IMO.

+1.     I've never used it in my mower or snowblower, and each of them is still running great after 10 years.  

Stabilizer does work. But for the lawnmower and other small engines I drain or use all the gas, clean plug and put a bit of oil in the spark plug hole to keep things lubed. 1st pull in the spring for the last 10 years.

As for my 68 camaro I store with a full tank (to avoid condensation) with stabilizer added. Prevents having to rebuild the carb every spring. I didn't add it to a nother car before storage and it was a pain to get running again.

I doubt it would do any harm to add more stabilizer to the mower if that is the way you want to store it.