Lawn Mower Maintenance: Seasonal Checklist
Keep your STIHL lawn mower running like new. Blade sharpening, oil changes, air filter cleaning, and winter storage tips.
Pre-Season Checklist
Before the first mow of spring, change the engine oil if it was not changed in fall. Old oil contains acidic byproducts that corrode internal engine surfaces over winter. Use the weight and type specified in your STIHL owner's manual — typically 10W-30 for most climates.
Remove and inspect the spark plug. A healthy plug has a light tan electrode and intact insulator. Clean carbon deposits with a wire brush or replace the plug if the electrode is rounded or the insulator is cracked. Check the air filter — paper filters should be replaced, while foam filters can be washed with mild soap, dried completely, and re-oiled before reinstalling.
Blade Sharpening
Remove the blade by blocking the blade from rotating and loosening the center bolt. File or grind the cutting edge at the factory bevel angle, maintaining a consistent curve along the entire length. A sharp blade cuts grass cleanly; a dull blade tears it, leaving brown tips and opening the lawn to disease.
Balance the blade after sharpening by hanging it on a nail through the center hole. If one side drops, remove material from the heavy side until it hangs level. An unbalanced blade vibrates excessively, damages bearings, and creates an uneven cut pattern.
Sharpen blades at least twice per season for residential use and weekly for commercial mowing operations.
Air Filter & Fuel System
A clogged air filter chokes the engine, reducing power and increasing fuel consumption. Inspect the filter every 25 hours of operation. For dusty conditions, check weekly. Never operate the mower without a filter — dust ingestion destroys piston rings and cylinders within hours.
Use only fresh fuel mixed with STIHL two-stroke oil at the correct ratio. Fuel begins degrading after 30 days even with stabilizer. If the engine runs rough or stalls, suspect old fuel first. Drain the tank, clean the fuel filter screen, and refill with fresh mixed fuel.
Never store fuel indoors or near heat sources. Gasoline vapor is heavier than air and can pool in low areas, creating explosive conditions.
Winter Storage
Run the engine dry or add fuel stabilizer and run for 5 minutes to circulate treated fuel through the system. Remove the battery on cordless models and store at 40-60% charge in a climate-controlled space. Remove the spark plug, add a teaspoon of clean oil to the cylinder, and pull the starter cord slowly several times to distribute it.
Clean the underside of the deck thoroughly — dried grass buildup traps moisture and causes corrosion. Apply a light coat of spray lubricant to metal surfaces. Store the mower in a dry location, ideally covered with a breathable fabric cover. Inflate tires to maximum pressure to prevent flat spots during long storage.
