Airdale CPO, unless you are sure your bag is absolutely air tight, don't use Marvel Mystry Oil else you will wind up with a bound up engine. I've stored engines in both kerosene and plain old 30 weight mototr oil for years with no problem. Right now I have an old OS 4 cycle with the exposed rocker arms which has been stored in 30 weight oil since the mid 70's and it is still like new. kerosene is also an excellent cleaning fluid for engines that have been crashed in sand or dirt.