When Is Fuel Too Old Too Run In An Efi Motor...

If it wasn't stabalized, it starts deteriorating in about 6 weeks and keeps getting worse from there,,, I would say after about 4 months it's toast.

This Fuel Is 4 Years Old....now Were To Dispose Of 65 Gal. Of Fuel....

What do you mean by toast?

Toast, no good.

Drain the tanks and start fresh. It will be a lot cheaper to drain the tanks than to fix a detonated engine. The lawn mower will run forever on 65 gallons.

I wouldnt think 4 month old gas would be toast though.

4 years old yes!

It is not exactly trash, but it is not something I would run through a high dollar engine. I just wouldnt chance it. I start with fresh gas each season. I have seen too many people with holy pistons due to bad gas.
Cheap insurance.

I have always winter stored my boats with 1/4 tank or less. Fill it with fresh premium in the spring, no problems. After 4 years you might have problems getting your lawn mower to run on that stuff. I would agree that after 4 months gas will deteriorate.

anyone use "gas fresh start" additive in spring?

I learned this lesson the hard way.
After the hurricane I siphoned gas from the cars I have in storage and kept my daily driver out of the long gas lines.
It didn't smell like varnish, so I figured it was okay. WRONG ANSWER!

Don't gamble, it's not worth the injector trouble.