lawn mower won't start after winter

Lawn Mower Won’t Start After Winter: 10 Possible Reasons

After months of freezing temps, ice and wet conditions have probably caused great distress to your lawn.

As the sun shines again in spring, it’s time to nurse your lawn back to its pristine condition.

Your yard is begging for some TLC, and one of the major tasks you have to do is mow your lawn.

Unfortunately, you’re faced with a horrifying problem: your lawn mower won’t run.

We hope you find solace in knowing that it’s a common issue. In fact, there are several reasons why a lawn mower won’t start after winter.

Luckily, most of these problems have simple solutions, and you don’t have to replace your machine immediately.

Lawn Mower Won’t Start After Winter

There is nothing more frustrating than finding your precious lawn mower not working properly when you need it the most.

There are many reasons why your lawn mower won’t start after sitting in your garage or shed for several months.

Especially if you don’t practice regular lawn mower maintenance, here are the most common:

1. Dirty or Faulty Carburetor

The carburetor is the first thing you want to check when diagnosing starting problems in lawn mowers.

A corroded lawn mower carburetor is one of the most common causes of your equipment not starting properly after being unused for a long time.

While cleaning a dirty carburetor is a reasonably straightforward process, it’s best to take your equipment to a local mower repair shop if you are unsure how to detach and disassemble it.

Why would a carburetor be the culprit?

If you left gas in the mower tank over the winter, some of it might have evaporated and left residue in the gas tank and carburetor.

Aside from cleaning the carburetor, consider replacing some components that might be worn out already, such as the float needle, gaskets, and diaphragms.

2. Stale Petrol

Old fuel is another common reason a lawn mower won’t start after winter.

Hence, instead of adding clean fuel too early, it is best to fill the fuel tank just when you are about to use the mower.

Stale fuel can cause all sorts of problems in your equipment, including preventing it from starting and affecting its performance.

Take note that old petrol can go bad in as little as two to four weeks, so drain it before storing the mower over the winter months.

If you fail to do so before tucking it away, drain the old fuel using an oil siphon or extractor when you take it out of storage. Then, fill it with fresh fuel before use.

3. Incorrect Fuel Injection

Faulty, dirty, clogged, or leaking injectors can cause starting issues and rough engine performance.

Old fuel, dirty oil, and carbon residue can cause fuel injectors to clog. Once it happens, no amount of intake or fuel injector cleaner can solve the problem.

The best way to deal with this problem is to remove the injector from the lawn mower engine and have professionals clean them.

If your fuel injectors are dirty, you don’t need to replace them right away. In such cases, you only need to take them off and clean them with quality fuel injection cleaners.

4. Faulty Spark Plug

Is your lawn mower still not starting after cleaning the carburetor, replacing the stale gas, and checking the fuel injectors?

That’s not to say you have a broken lawn mower. If you’re lucky, it could just be a problem with the spark plug.

A faulty or dirty spark plug can cause starting problems in lawn mowers.

Aside from difficulties in getting the engine to fire up, other signs of spark plug problems include:

  • Having to tug extra hard than usual on the rewind
  • Engine losing power while mowing
  • Gas running out quicker than it used to

Replacing the spark plug is an easy and inexpensive solution. Depending on the brand type, spark plugs cost anywhere from $2 to $10.

If your spark plug isn’t damaged or worn out, you could just clean it.

why lawn mower won't start after winter?

5. Choke Issues

If you are having trouble starting your mower, it could be that the choke butterfly isn’t closing properly.

To fix this, you must remove the carburetor’s air filter assembly, follow the throttle linkage cable, and pull things back using a pair of pliers.

It is also possible that the whole arm holding the choke valve is somehow pushed too far toward the carburetor.

Another possible reason is that the choke system of your mower gets flooded.

If this happens, you must drain fuel from the combustion chamber to the point when your mower is fine to start again.

6. Stale Oil

When you put fresh lawn mower oil into the engine’s crankcase, it should be golden or amber. Heat, dirt, and agitated air can get into the crankcase and affect the oil quality over time.

As a result of these, the oil’s ability to coat and protect the engine components is reduced.

This is why it is important to change the oil every 50 hours of operation or after every mowing season. Make sure to use the correct type of oil for your equipment and in the right quantity.

7. Low Battery

If your self-propelled mower refuses to start, you first want to check the battery.

Due to extreme weather exposure, batteries for lawn mowers tend to drain, fail, or even die.

Check if you properly installed the battery and if it has sufficient power. Make sure you also inspect for signs of visual damage.

Obviously, the battery needs to be dry. Wet lawn mower batteries can lead to short circuits and overheating.

Next, check for bad connections. When you start charging the battery, the contacts on the battery pack must be in place.

Most battery chargers have a light indicator to show you the precise battery level and whether or not it is charging.

Lastly, check for any signs of clogging of collected debris or grass clippings.

If you are not getting a response from the battery after checking all the other components, it is most likely an issue with the start switch.

If that’s the case, you may need to replace it.

8. Ignition Coil Issue

Bad ignition coils can make it difficult for your lawn mower to start.

A major sign of faulty ignition coils is when your engine only runs when you wiggle the spark plug wire.

Other symptoms to watch out for are when the mower:

  • Overheats after only a few minutes of mowing
  • Doesn’t shut down when you disconnect the spark plug
  • The engine cranks but won’t start

In most cases, you must replace the ignition coil, and that should do it.

You can also check if the carburetor is clogged. If yes, remove the carburetor bowl, thoroughly clean it, and reassemble it.

9. White Smoke Issues

Some lawn mowers have white smoke issues after winter.

It usually happens when you move the equipment into a sloping position, with one side incorrectly higher.

White or blue smoke from your machine may also indicate an oil spill on the engine.

If you recently changed the oil and it’s emitting white smoke, it could be that you accidentally spilled some oil onto the engine.

You can solve the problem by restarting the mower and letting the spilled oil burn off.

10. Compression Issue

Compression refers to the pressure that builds up inside the combustion chamber when the air and fuel are squeezed and a spark is applied.

Low compression happens when the pistons or the seals around them are worn.

To fix this, locate the ignition wire running from the spark plug to the distributor. If the plug is loose, compression might leak through the hole it’s creating.

Next, check if the bolts that hold the top of the engine cylinder are in place. They can allow compression to leak out from the cylinder if they are loose.

Get Your Lawn Mower Ready

If your mower won’t start after months of hiatus, there is nothing to panic about. This issue is more common than you think, and several possible reasons exist.

We’ve just discussed the 10 most common causes of start problems in lawn mowers.

Luckily, most of these problems have easy, inexpensive solutions you can do on your own if you know proper mower maintenance.

Most often, your mower’s engine only needs cleaning and an oil or gas change. If necessary, you might need to repair or replace worn-out parts, especially when they only cost a few bucks.

If the issue still persists after trying to resolve the issue on your own, it’s a good idea to ask for the help of a professional mechanic.

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