How To Start Lawn Mower After Winter

Spring is here, and you’re ready to tackle that overgrown grass. But your lawn mower sat through the cold months and now it won’t start. This is a common frustration, and knowing how to start lawn mower after winter is a key piece of seasonal maintenance. A lawn mower that sat through cold months often needs specific attention before it will start. The good news is that with a few simple checks and procedures, you can usually get it running smoothly again in no time.

This guide will walk you through the essential steps. We’ll cover everything from checking the fuel to inspecting the spark plug. Following these steps will save you time and money, and help you avoid the need for costly repairs.

Before you even attempt to pull the starter cord, there are several critical areas to inspect. Jumping straight to starting can sometimes cause damage if old fuel has gummed up the engine. A systematic approach is your best bet for a quick and successful spring start.

Safety First: Preparing Your Workspace

Always begin by ensuring you are working in a safe environment. This protects you and your equipment.

Work in a well-ventilated area, preferably outdoors or in an open garage.
Disconnect the spark plug wire to prevent any accidental ignition while you are working on the engine. This is the most important safety step.
Allow the engine to cool completely if it has been run recently.
Have a clear, flat surface to work on and gather your basic tools, like a socket set, screwdrivers, and fresh fuel.

Step 1: Inspect And Manage The Fuel System

Old gasoline is the number one reason a mower won’t start after winter. Gasoline begins to degrade in as little as 30 days, forming varnish and gum that clogs the carburetor and fuel lines.

Draining Old Fuel

If you left fuel in the tank over winter, you need to remove it. Use a siphon pump or a turkey baster dedicated to this task to extract as much old fuel as possible from the tank. Dispose of it properly at a local hazardous waste facility.

Checking The Fuel Line And Filter

Inspect the fuel line for cracks or brittleness. If your mower has an inline fuel filter, check if it’s discolored or clogged. A clogged filter will prevent fuel from reaching the engine.

Adding Fresh Fuel

Fill the tank with fresh, clean gasoline. For most small engines, using fuel with an ethanol content of 10% or less is advisable. For long-term health of the engine, consider using a fuel stabilizer with every tank, especially the last one before storage.

Step 2: Check And Change The Engine Oil

Oil is the lifeblood of your mower’s engine. Over time, it breaks down and can become contaminated.

Place the mower on a level surface.
Locate the dipstick, wipe it clean, reinsert it fully, and then pull it out again to check the oil level. It should be between the two marks.
If the oil is low, top it up with the type recommended in your owner’s manual. If the oil is very dark, gritty, or smells of gasoline, it’s time for a full change.
To change it, locate the drain plug underneath the mower, place a pan beneath it, and drain the old oil. Refill with the correct amount of new oil.

Step 3: Examine The Air Filter

A dirty air filter restricts airflow to the engine, causing it to run poorly or not start at all. There are two main types: paper and foam.

Remove the air filter cover and take out the filter. Hold a paper filter up to a light source. If you can’t see light through it, it needs to be replaced. For a foam filter, wash it gently in warm, soapy water, rinse thoroughly, and let it dry completely. You can apply a few drops of clean engine oil to a foam filter and squeeze it to distribute the oil evenly before reinstalling.

Step 4: Inspect The Spark Plug

The spark plug provides the ignition for the fuel-air mixture. A fouled or damaged plug won’t create a spark.

Disconnect the spark plug wire (you should have already done this for safety).
Use a spark plug socket to carefully remove the plug.
Inspect the electrode end. It should be a light tan or gray color. If it’s black and sooty, covered in white deposits, or the electrode is eroded, replace it.
Check the gap on a new or cleaned plug with a gap tool, setting it to the specification in your manual (typically between .028 and .035 inches).
Thread the new plug in by hand to avoid cross-threading, then tighten it snugly with the socket. Recconect the spark plug wire firmly.

Step 5: Assess The Battery (For Electric Start Models)

If your mower has a push-button electric start, a dead battery is a likely culprit. Remove the battery and clean any corrosion from the terminals with a wire brush and a solution of baking soda and water.

Test the battery with a multimeter. A fully charged 12-volt battery should read around 12.6 to 12.8 volts. If it’s below 12.4 volts, it needs to be charged. If it doesn’t hold a charge, you will need to replace it with a new one of the same size and voltage.

Step 6: Cleaning The Mower Deck And Blades

While not directly related to starting, this is crucial for performance and safety. A clean mower cuts better and is less likely to rust.

Tip the mower on its side, but make sure the air filter and carburetor side are facing up to prevent oil and fuel from leaking where they shouldn’t.
Use a putty knife or scraper to remove caked-on grass clippings from under the deck.
Inspect the blade for nicks, bends, or dullness. A dull blade tears grass, leading to a brown, unhealthy lawn. Sharpen or replace the blade as needed, ensuring it’s balanced.

The Final Starting Procedure

Now that you’ve completed all the pre-start checks and maintenance, it’s time to try starting the engine. Recconect the spark plug wire if you haven’t already.

If your mower has a fuel valve, turn it to the “On” position.
If it has a primer bulb, press it 3-5 times to draw fuel into the carburetor.
Set the engine speed control to the fast or start position.
For a recoil start mower, pull the starter cord with a smooth, steady motion. Don’t yank it violently.
For an electric start, simply turn the key or push the button.
If it doesn’t start after a few pulls, wait a minute and try again. Flooding the engine is possible.

Troubleshooting Persistent Problems

If you’ve followed all steps and the mower still won’t start, here are a few other areas to check.

Carburetor Issues

The carburetor mixes air and fuel. Old fuel can leave deposits that clog its tiny jets and passages. You may need to clean the carburetor bowl and jets with carburetor cleaner. In severe cases, a rebuild kit or replacement might be necessary.

Checking For Spark

To confirm the spark plug is working, carefully remove it, reconnect it to the wire, and touch the metal base of the plug to a clean, unpainted metal part of the engine. Pull the starter cord and look for a bright blue spark. No spark indicates a problem with the plug, wire, or ignition coil.

Compression Loss

While less common, an engine with low compression due to wear will struggle to start. This is a more serious issue that often requires professional repair.

FAQ: Starting Your Lawn Mower After Winter

Why won’t my lawn mower start after sitting all winter?

The most common reason is old, degraded gasoline clogging the carburetor and fuel system. Other typical causes include a dirty air filter, a fouled spark plug, or stale oil.

Should I use a fuel stabilizer?

Yes, it is highly recommended. Adding a fuel stabilizer to fresh gas before storing your mower for the winter prevents the fuel from breaking down and forming gums. This makes spring starting much easier.

How do I start a lawn mower that has been in storage?

Follow the systematic process outlined above: manage the fuel, check the oil, inspect the air filter and spark plug, and then attempt to start. Always begin with safety by disconnecting the spark plug.

Can bad gas cause a lawn mower not to start?

Absolutely. Gasoline that has been sitting for months loses its volatility and forms sticky residues that block the small passages in the carburetor, preventing the engine from getting the fuel it needs to run.

What is the easiest way to get a lawn mower running after winter?

The easiest way is proper pre-winter preparation. However, for a mower that was not prepared, the quickest fix is often to completely drain the old fuel, replace it with fresh gas, and install a new spark plug. These two steps resolve a majority of post-winter starting issues.

Getting your lawn mower running after a long winter doesn’t have to be a struggle. By understanding the common problems caused by inactivity and adressing them methodically, you can ensure a reliable start every spring. Regular maintenance, especially proper fuel management before storage, is the key to avoiding these issues altogether. With this guide, you’re equipped with the knowledge to handle this seasonal task confidently and get back to a well-manicured lawn.