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How to Store Your Lawn Mower for Winter

10/31/2019 5:00:00 AM

​Instructions for wi​​nterizin​g a zero turn mower

I​t’s that time of year again. Time to pack our lawn tractors and zero turn lawn mowers away for the winter. New homeowners or those new to outdoor power ​​equipment might not know much about fuel systems or gasoline engines, and that’s OK. We’re covering the what you need to do before putting your lawn mower into storage, why it’s important and how to do it.

​​Stabili​​ze th​​​​​​​e gasoli​​ne in the tank

Stabilizing ​​​your lawn mower fuel is the most important task to complete before putting your lawn mower into storage. If your mower sits idle longer than 2 weeks​ and it’s powered by gasoline or diesel, you’ll need to add fuel stabilizer. It sounds complex, but it’s very easy.

Why do I need to ​​s​tabilize gas in my lawn mower?

​Think of gasoline as fresh fruit. A mango is great after it’s been plucked from a tree and for a few days after, but it doesn’t take long for it to go bad. Same goes for gasoline. When gasoline is exposed to the air, it oxidizes and deteriorates. This makes it more difficult to ignite and, if left long enough, it could eventually render into a thick, jelly-like substance that becomes both useless and problematic.

The same happens to the fuel in a lawn mower tank and throughout the fuel system when left untreated for long periods of time. When that fuel g​oes bad, it’s costly for more than one reason. Even the slightest amount of bad, gummed up fuel can clog the fuel lines and the super-tiny hole in the carburetor jet.

When this happens, it chokes the fuel flow and blocks it from reaching the engine, preventing the engine from starting or running.

How do I stabilize gas​​ in my lawn mower?

Stabilizing fuel correctly requires attention to a few easy-to-follow instructions. You can​’t simply pour an entire packet or an entire bottle of fuel stabilizer into a gasoline tank and call it finished. Refer to your operator’s and engine manuals for details on your lawn mower, but most zero turn mowers follow these simple steps:

  1. ​​​Determine ho​​​​​w long it’s been since the fuel in your lawn mower tank was purchased. 

Gasoline goes bad in as little as two weeks, and that clock starts ticking as so​on as it’s pumped at the gas station. And ​no matter what you try adding to old fuel, gasoline cannot be rejuvenated and brought back to a stable state if it has already gone bad. ​

If the fuel ​in y​​our lawn mower tank was pumped more than two weeks ago, either drain it and dispose of it responsibly, or use it up completely.

  1. Add Fuel ​Sta​​bilizer

If the gasoline is fresh or less than two weeks old, add a quality fuel stabilizer to the tank according to the instructions on the stabilizer packet or bottle. The amount of fuel stabilizer to be added depends on the amount of fuel left in the tank. Estimate the amount of fuel in the tank, look for the stabilizer-to-gasoline ratio instructions on the stabilizer packet or container and calculate how much stabilizer needs to be added.

​If old gasoline was drained from the fuel system, there could still be fuel residue in the carburetor, fuel lines and tank. If that’s the case, add some fresh fuel to the tank and stabilize it to help pr​event the residue from going bad and creating a clog.

  1. Start the engine a​​nd run the mower.

Starting the engine allows the stabilizer to fully incorporate with the fuel in the tank and the fuel lines. Be sure to wait long enough for that fuel to run through the fuel system. This only takes about five to 10 minutes, but it’s critical to allow the engine enough time to cycle the treated gasoline through the entire fuel system. After enough time has passed with the engine running, close the fuel tank valve, if equipped, and allo​w the engine to “run dry” and stop on its own. Then, turn the ignition key to the off position and remove it from the unit.​

​C​​onnect a battery t​​​ender to the battery

Life spans of batteries in cars and outdoor power equipment shorten when not used for lo​​ng periods of time. This includes your zero turn lawn mower or tractor battery while it’s sitting in storage.

When ​​not in use for extended periods, batteries can discharge and lose their charge capacity. To keep your battery in good health for next season, connect the battery to a battery tender or trickle charger.

  • A trickle charger applies a constant, weak charge to the battery and will keep it fully charged through the offseason.
  • Battery tenders charge a battery, stop charging once the battery reaches a full charge, and will start charging again once the battery drops below a certain voltage.

Both options are good solutions for maintaining your mower's battery. Some resources suggest a battery tender is a better choice because a constant ch​​arge from a trickle charger can potentially damage a battery. In any case, give your battery attention while it’s being stored. If you choose, the battery can be removed from the unit and charged in an area close to an outlet.

Not su​re where to start? Check out our video on how to correctly disconnect a battery from a zero turn lawn mower.

​​Change lawn ​mower o​​​il and oil filter

Oil changes aren’t technically required before putting a lawn mower into storage. Oil left for a year or two won’t deteriorate or gel like gasoline,​ nor will it clog any narrow passages, so the system doesn’t need to be drained or treated. However, it’s extremely important to change your lawn mower oil and its oil filter at least once per year, or according to the maintenance intervals outlined in the engine manual for the unit.

Oil changes are easy to perform, inexpensive, don’t take much time and are extremely crucia​​l to the health of your engine.

Why do I need to change​​​​​​ the oil in my lawn mower?

A lawn mower engine is a mower’s power plant. Without it, grass doesn’t get cut. And without regular oil changes, major malfunctions could occ​​ur long before the engine’s life cycle is over, costing you unnecessary repair bills and frustration.​

The metal parts inside an engine moving at thousands of revolutions per minute have friction, and friction is the enemy. Not only does friction wear those delicate parts (very slowly and over time, of course), friction​​​ also creates heat, and heat is bad for an engine. Over time, heat from engine combustion and friction deteriorates the lubricating values of its oil – making it less effective at protecting an engine.

Oil degradation and contamination is unavoidable regardless of its use in light, norm​​al or extreme conditions, which is why it’s important to perform oil changes regularly. Running an engine with dirty or degraded oil can damage it. Changing oil regularly strengthens reliability, ensures strong performance and protects your investment.

Steps for Chang​​​ing Oil i​n a Zero Turn Lawn Mower

  1. Remove the engine oil drain plug and allow the used oil to drain into a container. Use a funnel if necessary.

  2. Once drained, reinstall the drain plug and tighten to the specification in the engine manual.

  3. Remove the oil filter, allow the oil to drain from the filter and dispose the filter.

  4. Dip the tip of your finger in the used oil and apply a thin layer of it around the rubber gasket of the new oil filter.

  5. Install the new oil filter and tighten according to the specifications in the manual. Ensure the filter is not cross threaded and is tight against all sides of the filter port.

  6. Remove the cover from the engine fill port and add the correct volume and type of engine oil listed in the manual.

  7. Reinstall the fill port cover.

  8. With the parking brake on, start the mower and visually inspect the engine to ensure oil isn't leaking. Stop the engine when complete.

​​​​​Change transa​​xle​​​ fluid and filter

Wh​at is transax​le fluid?​​

If you’re not familiar with a transaxle in a zero turn lawn mower, you might know it by another ​​name like hydros, hydrostatic transmissions, or pumps. However you prefer to call it, it’s the same component. If the hydros on your mower are maintenance-free, then you don’t need to touch them. If you have larger acreage and own a larger mower with serviceable transaxles, its oil and oil filter will need changing.

Like engine oil changes, this isn’t a maintenance procedure that needs to be compl​eted before storage, but it will be necessary at some point of the year.

How to change transaxle fluid​

This procedure is a bit more​ complex, which is why we suggest those who are inexperienced with maintenance to rely on the technical expertise of their local Ariens de​aler.

For those who are comfortable doing the procedure themselves, we provided basic steps to a hydro oil cha​​nge procedure below, but always refer to your operator’s manual for the safety information and instructional details when doing the procedure.

  1. Operate the unit for a few minutes to warm the fluid.

  2. Stop the unit and wait for hot parts to cool.

  3. Remove the transaxle filter guards, if equipped.

  4. Remove oil filters, drain filters and dispose.

  5. Remove the fill plugs from transaxles.

  6. Wipe the filter mounting surfaces clean.

  7. Lubricate rubber gasket on new oil filters with hydraulic oil.

  8. Install filters onto transaxles and torque to specification.

  9. Reinstall filter guards with original hardware and torque to specification.

  10. Add the correct type of hydraulic oil to the transaxles until oil appears at the bottom of the oil fill openings.

  11. Reinstall oil fill plugs and torque to specification.

  12. Add hydraulic oil to the expansion tanks until fluid level meets the cold fill line.

  13. Purge the hydraulic system according to instructions in manual.

​​​Change lawn mower air filter

Engines intake air to create t​he combustion that powers them. And just like humans, engines breathe the same air we breathe, but not without filtering it first. Dust, dirt and other debris sucked in through an engine’s air intake can damage its delicate parts, which is why each engine comes equipped with an air filter. As the engine ‘inhales,’ the filter catches that debris and prevents it from entering the engine.

​Even the smallest airborne particles can damage an engine. And while the engine air filter does its job catching these particles, over time it collects mo​re and more debris until it gets so full that it becomes less effective. Additionally, restricted airflow because of a clogged filter makes an engine work harder and reduces its efficiency. This is why it’s important to check the filter regularly and replace it when needed.

Engine air filter replacements are not necessary to complete before seasonal storage, but it’s a good practice to do it now so it’s not forgotten later.

​Other lawn mower storage m​​aintenance

The information above is the bulk of the heavy lifting, but there are other maintenance points deserving of your attention before putting your mower into storage. ​Though they aren’t critical to complete now, it’s smart to check these off the list today so you’re ready for next season:

  1. Applying lubrication to all grease fittings (usually on caster wheels and hubs), pin points and other connections

  2. Checking lawn mower belts and replacing, if necessary

  3. Checking lawn mower blades and sharpening or replacing, if necessary

  4. Cleaning underneath a lawn mower deck for good airflow and a superior cut quality

  5. Adjusting the deck level and pitch

For other zero turn lawn mower maintenance tips subscribe to the Ariens channel on YouTube and sign up to receive emails from ariens at

Want a quick rundown on winter storage? Watch our lawn mower storage video here for a brief overview of how to store your mower.