Does two stroke oil get old???

[Sutty]

I was wondering if the oil in my reservoir deteriorates over time. I prob still have two gallons in my three gallon tank from last year so it will be in there for a while yet this summer.

[marine_man]

It might a little bit, but I think you'll be just fine waiting until this summer. I'd top it off before you go, but I think you'll be just fine.

marine_man

[theoilman]

The shelf life of AMSOIL's 2-stroke oils is 2 years. So if AMSOIL you have no problem.

The shelf life comes primarily from the dyes used. Long term - over 2 years - the dye will tend to separate. The oil can still be safely used older, just shake the bottle to thoroughly remix. With pre-mix once mixed in gas there is no separation problem.

Any other brands you will have to find someone else to help you.

[Fredd]

theolilman, Is shelf life applicable when the seal is broken on the container like when the oil is put in the reservoir?? I would assume not. I think this was Sutty's question.

[theoilman]

First of all I've personally observed it in only the Saber oils- both Saber Professional for air cooled engines and Saber Outboard premix for outboards - I've seen it in a sealed container. The dye for the 100-1 is heavier. It doesn't separate once mixed in gas.

I've never personally seen it in HPI (for oil injected outboards). The dye in HPI is different and should be slower to separate. It would be possible to separate in the bottle or in the oil container on the engine either one, but is far less likely on the boat because of the agitation (constant motion) on a boat will tend to keep it mixed.

Any brand other than AMSOIL I do not know about.