Bryan I'am going to offer a back handed apology . Your original , subject title was chainsaw fuel . Which is a combination of oil & some form of gasoline . I now realize you were mostly concerned with proper storage of today's available gasolines . However to understand that , you must understand the variable oils available to mix in Efuel & non Efuel . There are 4 Groups of Oil currently rated by Jaso Standards I, II , III & IV . Otherwise recognized as FA & FB are all but obsolete . FC & FD are the most stringent testing protocol' s recognized today . All these oils Mineral (Dino) through various Premium Synthetics ( Ester vs Polyethel ) effect the performance of the fuel you utilize . Anyhow as I previously mentioned you have to match the oil & fuel to your engines performance application . e.g.: Recreational low compression low heat & pressure & relative low rpm operation or Racing high compression , high heat & temperature & relative high rpm operation . I think you understand various oils have additives added to the base pale oil to benefit in reducing friction ( heat) , oxidation stabilizers for (thermal viscosity break down) prevention & dispersent additives for moisture entrainment protection & viscosity stabilizers to prevent galling from extreme pressure on loading on metal to metal surfaces . ( rings & bearings ) . A lot to think about and understand . In a nutshell , most run of the mill oil do a adequate job in recreational engine usage . However only Premium Synthetic provide adequate protection in severe operative parameters and during storage . Amsoil Sabre for small hand held engines has everything req'd , a few other manufacturers do also . The majority though do not provide this protection during storage . Therefore , fuel additives such as Stabil , Startron , Seafoam , Marvel Mystery Oil etc . I prefer Startron as a stabilizer for obvious reasons as I already advised . So sorry for the lengthy dialogue & hi jacking of your thread , hope it has helped you in some manner !