Short answer
Before storage, stabilize or drain the fuel as the manual directs, change four-stroke crankcase oil, fog cylinders where the maker calls for it, change outboard or sterndrive gear lube, protect exposed metal, and follow the manufacturer’s freeze-protection steps for anything that holds water.
Fuel: stabilize or drain
Gasoline left in a tank, fuel line or carburetor over winter can varnish and gum. Most equipment makers give one of two instructions: add a stabilizer and run the engine so treated fuel reaches the carburetor or injectors, or drain the fuel system completely. Follow the one in your manual.
AMSOIL Gasoline Stabilizer is sold for equipment being prepared for storage, and Quickshot is a gasoline treatment and stabilizer for powersports and small-engine fuel systems. Measure the dose against the actual amount of fuel; do not estimate it.
| Equipment | Fuel | Oil and lubricants | Other |
|---|---|---|---|
| Push or riding mower | Stabilize and run, or drain per manual | Change crankcase oil | Clean the deck; charge or remove the battery |
| Chainsaw, trimmer, blower (two-stroke) | Empty the mixed fuel or run it dry per manual | None separate from the fuel mix | Clean the air filter and bar; protect the chain |
| Four-stroke outboard | Stabilize per manual | Change crankcase oil and lower-unit gear lube | Fog per manual; flush and drain cooling water |
| Two-stroke outboard | Stabilize per manual | Change lower-unit gear lube; fill the injection reservoir | Fog per manual |
| Sterndrive or inboard | Stabilize per manual | Change engine oil and drive gear lube | Winterize the raw-water system as the maker directs |
| Generator | Stabilize or drain per manual | Change oil | Exercise it monthly if kept ready |
Source: AMSOIL Gasoline Stabilizer.
Source: AMSOIL Quickshot.
Four-stroke engines: change the oil first
Many equipment manuals call for an oil change before storage, because used oil carries moisture and combustion byproducts that sit against engine parts all winter. Change the oil while the engine is warm, then run it briefly to circulate the fresh oil.
Use the viscosity and oil standard the manual lists. AMSOIL’s small-engine oil bulletin lists its synthetic small-engine oils for gasoline engines, off-road diesel engines and certain transmissions, and notes they contain no friction modifiers and meet JASO wet-clutch standards. Four-stroke crankcase oil is not two-stroke premix oil.
Source: AMSOIL Synthetic Small-Engine Oil data bulletin G2217.
Fogging the cylinders
Fogging oil coats the cylinder walls, rings and valves to limit corrosion during storage. Follow the fogging oil’s label and the engine manual: some procedures spray into the intake while the engine runs, others into each spark-plug hole with the engine off.
Many fuel-injected outboards and powersports engines have their own storage or fogging mode. Use the manufacturer’s procedure for those engines.
Boats: lower units, sterndrives and anything that holds water
Drain and refill outboard lower units and sterndrives with the gear lube the maker specifies. Look at the old lube as it drains: a milky color suggests water has entered past a seal, which is better found in October than in May.
AMSOIL’s marine gear lube bulletin lists its 75W-90 for fresh- and saltwater lower units and sterndrives that require 75W-90 or 80W-90 gear lube, including Mercury, Yamaha, Honda, Suzuki and Mercruiser Bravo units. A gear-lube pump makes refilling from the bottom drain easier.
Engines, sterndrives, water heaters and plumbing that hold water can crack when it freezes. Follow the engine maker’s winterizing procedure, including the type of antifreeze it specifies for raw-water systems.
Source: AMSOIL Synthetic Marine Gear Lube data bulletin G2044.
Protect metal, batteries and trailers
Coat exposed metal, linkages and tools with a corrosion protector suited to the surface. AMSOIL MP Metal Protector is a spray for lubrication and corrosion protection; Heavy-Duty Metal Protector leaves a longer-lasting coating for parts in storage.
Charge batteries and either keep them on a maintainer or remove and store them as their maker recommends. Grease trailer bearings and fittings before the trailer sits.
Sources checked . Prices and product guidance may change.
Frequently asked questions
Should I stabilize fuel or drain it?
Follow the equipment manual. Some makers prefer a stabilized, full tank; others want the carburetor or the whole fuel system drained.
Do I need to change the oil if I only used the mower a few times?
Many manuals call for an oil change before storage regardless of hours, because of moisture and combustion byproducts in used oil. Follow your manual’s schedule.
Can I fog a fuel-injected engine?
Only as its maker directs. Many fuel-injected engines have their own storage procedure or fogging mode.
General maintenance information. Always follow your vehicle or equipment manufacturer’s requirements and the current product data. Questions? Email [email protected].
