I have 5 gallons of 15 % nitro / castor bean fuel
all containers are factory sealed stored in a cool environment
are they still good too run in a new OS Max engine
Thx
jim

With no reference to the fuels age fuel stored as you describe will last many years. If there's no contamination in it probably fine to use.

Thx A J
The fuel is ~ 3-4 years old

I know guys that have used fuel that was 30 years old in the factory sealed cans. Not a single problem - in fact, as compared to modern fuels..... the 30 year old stuff runs better than the modern stuff being made.