To make your engines and equipment last longer, it's recommended that you take certain steps to prepare them for storage in the winter and summer, and then also to get them ready for heavy use when you take them out of storage.
Winterization is a familiar term - you winterize a boat by getting it to be put away for storage when you stop using it before the cold weather starts.
Summerizing is the same principle, applied to the equipment you use a lot during the winter that is going to be packed away and not used during the hot summer months.
Winterizing is done for boats & marine craft, ATVs and garden equipment - the things you use a lot during the spring and summer, but don't use during the cold winter.
Summerizing is done for oil-fired home heating systems and snow blowers - the things you use during the winter but stop using when the weather gets warm.
The Bell Performance blog has several entries on recommendations for getting your small equipment, ATVs, and also your home heating system ready for the summer and winter - whether it's putting them away for storage or unpacking them for upcoming use.