Winterizing Your STIHL Lawn Mower: Step-by-Step
Proper winter storage prevents corrosion, fuel system damage, and battery degradation. Follow this checklist to protect your STIHL mower until spring.
Fuel System Care
Gasoline left in the tank over winter breaks down into varnish and gums that clog carburetor jets and fuel lines. You have two options: drain the tank completely or fill it to the top with fresh fuel treated with a stabilizer. We recommend the stabilizer approach because a full tank leaves less air space for condensation to form.
Add STIHL fuel stabilizer to the tank according to the label instructions, then run the engine for 5-10 minutes to circulate the treated fuel through the entire system. For cordless mowers, remove the battery and store it at roughly 50% charge in a climate-controlled space. Never leave a lithium-ion battery in an unheated shed through freezing temperatures.
Blade and Deck Maintenance
Remove the blade for sharpening, balancing, and inspection. Winter is the perfect time to address nicks and dull edges when you are not under pressure to finish a mowing session. Scrape the entire underside of the deck clean — dried grass buildup traps moisture against the metal and accelerates rust.
Apply a thin coat of spray lubricant or light oil to the blade mounting bolt threads and the deck underside to prevent seizing. Reinstall the blade with the correct torque setting from your owner's manual. A loose blade is dangerous; an overtightened bolt can strip threads or crack the mounting boss.
Final Storage Steps
Clean or replace the air filter. A dirty filter stored over winter can harbor moisture and mold that contaminates the engine on first startup. Wipe down all external surfaces and apply a light coat of wax or silicone protectant to painted and plastic surfaces to repel dust and moisture.
Store the mower in a dry, covered location. If you must store it in an unheated space, place a moisture-absorbing desiccant pack under the deck and cover the machine with a breathable fabric cover — never plastic, which traps condensation. For walk-behind mowers, store them level. For riding mowers, inflate tires to maximum recommended pressure to prevent flat spots.