How To Start A Riding Lawn Mower That Has Been Sitting For Years

Perhaps you’ve defaulted to a push lawn mower after you moved to a home with a smaller lawn. A large riding lawn mower might not make sense, so you pack it away in storage. Or, maybe you’ve neglected your yard for a couple of years (it happens), and the lawn mower has just sat, collecting dust. 

Either way, you’ve decided it’s time to break it out of storage and start using it again. However, your excitement runs out the moment it won’t start. Now what? Are there certain things you should check? We’re here to answer your questions, so continue reading to learn more!

How Do You Start A Riding Lawn Mower That Won’t Start?

After sitting for years on end, your riding lawn mower might be on strike. Perhaps it won’t start, or maybe you want to check the necessities before firing it up. Either way, here’s what you’ll need to inspect the system:

  • Gas can
  • Funnel
  • Oil dipstick
  • Oil drip pan
  • Screwdriver
  • Flashlight
  • Siphon hose
  • Spark plug wrench
  • Air compressor
  • Tire pressure gauge

The following sections outline a few areas to check if the mower won’t start or simply blows white smoke. They’re not in any specific order, so you can organize them however you prefer. 

Charge The Battery

After sitting for a while, the battery on your mower will lose charge. So, while you check over everything else, start charging the battery. If you don’t have a battery charger, you can always jump-start it later, but using a charger is easier. 

Before you start charging the battery, make sure you clean off any corrosion. Boiling water is a quick and easy way to eliminate built-up corrosion. Make sure the terminals are nice and clean before you start charging. 

Check The Gas Tank

Gasoline is a stable mixture, but it might break down after multiple years. So, if your lawnmower has been roosting for years on end, the gas in it is probably bad. Generally, it takes about three to six months for gasoline to break down, so the contents are likely unsalvageable after a few years.

Before filling the tank with fresh gas, you need to siphon the old gasoline. Stick one end of a siphon hose into the tank, then position a receptacle for the gasoline under the other end. Suck on the other end until gas begins to come out, then direct the hose down into the receptacle. 

It’ll continue to flow until the tank is empty. Once you drain the gas, dispose of it properly. As with oil, you can’t just throw gasoline away. 

Check The Oil

Checking Engine Oil

Oil doesn’t necessarily go bad, but it does collect pollutants and dirt after a while. It doesn’t hurt to check the oil while you’re at it. Take a peek at the color using the oil dipstick. If the shade resembles a light caramel color, it’s probably fresh and okay to use.

However, if the oil is black or dirty, you need to change it before you use the mower again. If you can, try to run the mower for a few minutes before starting the oil change, as this warms up the oil and makes it easier to drain. 

If that’s not possible, go ahead and locate the oil drain spout. Attach a drain tube to avoid making a mess. Position an oil drip pan underneath the line, then open the spout and allow it to drain. For a better flow, remove the dipstick while it drains. 

Once the oil stops flowing, close the spout. If your mower has an oil filter, change that while you’re at it. It’s probably on the opposite side of the engine. Use a strap wrench to loosen it, then remove it, making sure to catch any drips with the drip pan. 

After removing the filter, install an identical replacement and fill the oil tank with the correct oil. Use the dipstick to ensure you have enough in the tank. Dispose of the old oil properly.

Examine The Spark Plugs

In some cases, the spark plugs might be the culprit of a mower that won’t start. Locate the spark plug, then check for corrosion or damage. You should be able to easily find the plug, as there will be a black rubber wire connected to it. 

If you’re having trouble locating it, check the owner’s manual for a guide. Alternatively, check online. 

You’ll need to replace the spark plug if you find corrosion or damage. 

Remove The Air Filter

The air filter collects dust, even when it sits. Use the owner’s manual to locate the filter, then check it for dirt, debris, and damage. Replace the air filter as necessary, ensuring you purchase an identical replacement. Without an exact match, things won’t work out very well. 

Look For Rust

After years of sitting, your lawn mower probably collected rust here and there. Rust probably won’t be a problem if it’s only been sitting for a year or two, but after five to ten years, you’ll probably find rust. 

Using a flashlight, inspect every portion of the engine. Look for rust on each component, as this weakens the part. They might break when you use the mower, causing more issues after it happens. 

Replace any worn or rusted parts as soon as possible. 

Check The Tires

Over time, the tires on your lawn mower might begin to deflate slightly. If your mower has been sitting for a long time, there’s a good chance the tires are low. Generally, all it takes is a bit of extra air for them to be as good as new. 

Re-inflate the tires with an air compressor, using a tire gauge to ensure you don’t overfill them. Overfilled tires can cause a blowout. 

Let the mower sit for a while after filling the tires. If the tires leak air quickly or are flat, replace or repair them. 

Tighten The Brake Cable

When the brake cable is loose on your lawn mower, it might not start. So, check the tension on the cable by pulling the brake handle. While holding the brake handle, use your other hand to pull on the cable to see if there’s good tension or slack. 

If it’s loose, tighten it with a crescent wrench and a pair of vice grips. 

If you’re unsure whether the cable is your problem, try starting the mower while you hold the cable tight. If it starts, then this is the issue, and you’ll need to tighten the cable. 

Examine The Carburetor


Another area to add to your list is the carburetor. Although you don’t find them in most modern vehicles, riding lawnmowers still feature them. So, be sure to check the carburetor before you start the engine. 

If there was gasoline sitting in the engine and fuel lines when it was put away last, there’s a good chance there’s a sticky residue left over in the engine. This is caused by evaporated gasoline and is pretty easy to clean. 

All you’ll need to do is remove the affected piece, then soak it in vinegar. Or, use a specialized carburetor cleaner. Once the residue lifts, reinstall it. If you’re unsure how to remove the part, refer to the owner’s manual for exact instructions. 

Contact A Mower Repair Service Shop

In some cases, a more significant issue might be at play that is causing your mower to remain on strike, despite your best efforts. Once you’ve tried everything you can think of, even though nothing seems to work, you might want to consider enlisting the help of a repair shop. 

Reach out to a local shop for assistance. Some equipment rentals offer servicing for lawnmowers (among other things), so you can always check with them if there aren’t any repair shops in your town. 

How To Prepare A Lawn Mower For Long-Term Storage

Time can be hard on lawn mowers, but there are a few things you can do to make the transition back to active use easier next time. For example, if you live in an area with long winters, your mower will sit for months on end. 

So, to avoid the repair session at the beginning of the mowing season, be sure to do these things before storing it for the winter:

  • Drain the fuel: If you’re only leaving the mower for a few months, you can add a fuel stabilizer. However, if it’s going to be sitting for a while, drain the fuel tank completely.
  • Cover it: Use a protective cover, like a tarp or canvas cover, to protect the lawnmower from the elements. 
  • Disconnect the spark plug: Disconnect or remove the spark plug altogether before putting the mower away. This prevents an accidental engine start. 
  • Clean it: Before you pack it away for months on end, clean the debris and dirt off the mower. Remember to clean the blades, as these are particularly susceptible to rust. Let the machine dry completely before covering it and putting it away. 
  • Drain the oil: Draining the oil now eliminates an extra step in the next season. If the oil is fresh, simply drain it into an old jug and reuse it at the start of the next season.