15 Causes and Cures for a Non-Starting Self-Propelled Lawnmower

The grass can be kept at a manageable length with the use of a lawn mower. It helps maintain a neat and tidy lawn and keeps pests like mice and moles away.

If it refuses to turn on, you should make it a top priority to get it going again so that you may avoid the hassle of a neglected lawn.

If your self-propelled mower won’t turn over, check the gasoline, the air filter, the fuel line, the fuel filter, the carburetor, the spark plug, the ignition coil, and the recoil.

When the battery, ignition switch, or starter solenoid in a self-propelled mower are malfunctioning, the machine may not start.

Observe all warnings and instructions provided by the manual. Before making any adjustments or repairs, the spark plug must be removed.

self-propelled mower

How to Fix Common Issues When Starting a Self-Propelled Lawn Mower (Quick Reference Chart)

Zero Fuel in TankRefill your gas tank. You should check to see if there is a fuel leak.
Misplaced Fuel Control ValveIf the fuel shut-off valve was used to turn off the fuel supply, turn it back on.
Low-Quality or Outdated FuelIf the gas in the tank is older than 30 days, you should empty it. You should fill it up with new fuel that has been treated with a fuel additive to keep the fuel system clean and the moisture content low.
Mistaken ProcedureIf your gasoline filter is clogged, you need to change it.
Clogged Fuel FilterIf the fuel line is clogged and not allowing enough gas through, you should disconnect it. Remove the obstruction with compressed air after applying carburetor cleaner to release it.
Clogged Fuel LineIf the fuel line is clogged and not allowing enough gas through, you should disconnect it. Remove the obstruction with compressed air after applying carburetor cleaner to release it.
Clogged CarburetorThe carburetor must be removed before cleaning. Use a carburetor rebuild kit to replace any worn or broken components or get a brand-new carburetor altogether.
Contaminated Air FilterFix a clogged air filter. If it gets too dirty, damp, or damaged, throw it out and get a new one.
Spark Plug Debris or DefectUse a wire brush to clean a dirty spark plug. If a spark plug has turned a dark color, is broken, or has a burnt electrode, it needs to be replaced. The spark plug connection is only as good as its boot.
Faulty Ignition CoilDetermine if there is a break in continuity by using a multimeter. If there is a crack in the ignition coil, you will need to substitute it.
Bad RecoilIt’s time to re-string that rope that got all tangled up. Replace the entire recoil assembly if necessary due to damage.
Bad Fuel CapIf the gasoline cap is not perforated, the fuel tank cannot vent properly and must be replaced.
Bad Battery or Loose Connections (Electric Start)Make that the battery is fully charged, the fuses are not blown, any rust is cleaned away, and all connections are making solid contact.
Incorrect Ignition Switch (Electric Start)If the switch turns out to be bad, substitute it.
Faulty Starter Solenoid (Electric Start)Using these steps, inspect the starter solenoid. If broken, get a new one.

Causes of Self-Propelled Mower Failure to Start

The Gasoline Tank is Empty

You know that gas is necessary to maintain the lawn mower you bought. That doesn’t rule out the possibility that you missed the time since your previous gas refill or that you’ve acquired a fuel leak.

Having no gas may be the reason your lawnmower won’t start, and I just bring it up as a possible explanation because it’s easy to forget to look there first.

Look for fuel leaks and make sure the tank isn’t empty. Fix the fuel leaks and replenish the tank.

The Fuel Valve is Closed on a Self-Propelled Mower

A fuel shutoff valve is included on some models of self-propelled lawn mowers. It’s often situated toward the gasoline tank’s base.

Make that the mower’s fuel shut-off valve isn’t blocking fuel delivery. While in storage, transit, or maintenance, the fuel supply may have been cut off using this valve.

Low Quality or Old Gasoline for Your Self-Propelled Mower

When fuel is stored for long periods of time without being used, it can cause serious problems. After only 30 days, gas can start to degrade and become unstable.

Water vapor from the atmosphere is drawn to the ethanol in the gas. The combination of water and ethanol can leave a sticky film or a varnish behind. This will lead to fuel constraints, which will make a self-propelled mower operate poorly or prevent it from starting altogether.

Your lawn mower will benefit from having its fuel used within 30 days of purchase. Use a fuel stabilizer like Sea Foam or STA-BIL to extend the life of your gas if you won’t be able to use it all before it goes bad.

In addition to maintaining fuel stability, Sea Foam also removes moisture and cleans the fuel system. Find out more about Sea Foam and how to use it by reading this.

In the event that you discover stale gas in your lawnmower, you should empty the tank using a fuel siphon pump. You need to put in new gas that has been treated with a fuel additive such as Sea Foam. Get fuel with at least 10% ethanol and an octane rating of 87.

Both two-cycle and four-cycle motors need gasoline as fuel, whereas two-cycle engines can also run on a mixture of gas and oil (not mixed with oil). Here you may learn more about what fuel is best for your lawn mower.

Misuse of a Self-Propelled Lawnmower

For the protection of the user, self-propelled mowers feature a bail lever or handle. Upon releasing the lever, the engine will shut off instantly.

You can’t get the mower going unless you pull the lever back and keep it pressed against the handle. If the operator is not there to depress the bail lever, the mower will not start.

The bail lever must be kept against the handlebar when using an electric starter or the recoil when using a pull-start. When you wish to stop the mower, you must release the bail lever.

Fuel Filter Clogged on a Ride-On Mower

The gasoline filter sieves the fuel so that harmful debris doesn’t make its way into the fuel system and your engine. Blockage of the fuel filter might prevent fuel from getting to the engine. If the filter becomes clogged, you should clean it or replace it.

In the case of a lawnmower that requires an inline gasoline filter to be put between the fuel lines, make sure the arrow on the side of the new filter faces in the direction of fuel flow. Make sure the arrow is pointing toward the carburetor and not the gas tank.

However, an inline fuel filter is not standard on all self-propelled mowers. If that’s the case, check the mower’s parts diagram to see if a different kind of gasoline filter is installed. Some people who propel themselves utilize a filter or screen that is attached to the engine.

Restrictions on a Push Mower Caused by a Clogged Fuel Line

The gasoline line might become clogged with grime and deposits from using stale fuel. To inspect the fuel line, turn off the gasoline supply. There may not be a valve on your self-propelled lawn mower, but you may still halt the gasoline flow by crimping the line with fuel pinch-off pliers.

Take the carburetor hose and put it somewhere safe. Turn on the gasoline supply and double check that it is filling the tank. The fuel tank must be positioned underneath the storage container. Unless a gasoline pump is used, fuel will not flow uphill.

Stop the fuel flow and disconnect the fuel line from the mower if there is a slow trickle of gas entering the container. Clean the line with carburetor cleaning to remove the obstruction. Unclog the line by blasting compressed air through it.

When necessary, use carburetor cleaner and compressed air to try again. If the fuel line is too clogged to unclog, a new fuel line must be installed.

Self-Propelled Mower with a Filthy Carburetor

The carburetor controls the ratio of fuel to air that is sucked into the engine and burned in the cylinder. Gummed up with old fuel, a dirty carburetor prevents its parts from doing their jobs.

Your self-propelled mower may not start because the carburetor is blocking gas flow.

Once you’ve established that gasoline is reaching the carburetor, you can clean it by removing the air filter and spraying cleaner into the intake. Launch the lawn mower. Take apart the carburetor and clean it if the engine fires up, idles for a while, and then dies.

Clogged Self-Propelled Lawnmower Air Filter

Blocking the air filter prevents the engine from receiving the necessary amount of air for combustion and might cause the mower to overheat. In general, you should change your air filter once a year. The upkeep doesn’t end there. At regular intervals throughout the season, you must inspect and clean your air filter.

Maintaining a Paper Air Filter:

  • Take out the filter and throw it away.
  • You should clean the housing and the cover by wiping them down. The air inlet should not be allowed to become clogged with dirt.
  • To remove dust from the paper air filter, tap it against something hard. The dirt is being loosened and allowed to fall to the floor as a result of your efforts.
  • Then, place your filter in front of a light. You can safely keep using the paper if you can see through it. If the filter is exceedingly dirty, damp, or damaged, or if you are not receiving any light, you should get a new one.
  • Set up the filter and replace the cover.

How to Use a Foam Pre-Cleaner on a Paper Air Filter:

  • Care for your paper air filter by following the instructions given above.
  • The foam pre-cleaner can be cleaned with a solution of mild detergent and warm water.
  • The filter must be washed till the water comes out clear.
  • The best way to dry anything is to let it air out. (AVOID DILUTING FOAM PRECLEANER WITH OIL).
  • Replace the foam pre-cleaner and paper filter in the air intake.

Here’s how to clean a primary foam air filter, which is what most self-propelled mowers have.

  • Take off the foam air filter from the housing.
  • You should clean the housing and the cover by wiping them down. The air inlet should not be allowed to become clogged with dirt.
  • For a thorough cleaning, submerge the filter in a solution of mild detergent and warm water.
  • The filter must be washed till the water comes out clear.
  • The best way to dry anything is to let it air out.
  • Coat the filter with a thin layer of motor oil or foam filter oil. To drain extra oil from the filter, squeeze it. You want the oil to completely cover the filter, but not drip off of it.

If you want to know how to clean the filter on your mower but aren’t sure what kind it is, check the manual.

An Issue With a Self-Propelled Mower’s Spark Plug

When the tip of a spark plug is dusty, the porcelain is fractured, or the electrode is scorched, the plug is considered faulty and fouled. The deposits on the spark plug’s tip can be cleaned off with a wire brush.

If you notice that the tips of your spark plugs are particularly dark in color or are broken, you should replace them.

In accordance with the guidelines outlined in the owner’s manual, you must adjust the gap on your spark plugs. A spark plug with an improper gap or spark plug wires that aren’t securely fastened can prevent the engine from starting.

Problematic Ignition Coil on a Self-Propelled Lawnmower

You should inspect the spark plug before worrying about the ignition coil. Ignition coils are what supply power to spark plugs, allowing them to ignite and kick-start engines. To put it simply, if the spark plug isn’t working, the engine won’t turn over.

Using an ohm meter, make that the ignition coil has continuity. When a break in continuity is detected, the ignition coil must be replaced.

Self-Propelled Mower With Terrible Recoil

It’s possible that your mower’s recoil no longer works. Recoil repairs may include restringing a rope or replacing worn or broken pulleys, springs, or clips.

Occasionally, a simple restringing of the recoil will do the trick. Recoil parts will occasionally break and require replacement. Figure out how much money you’ll need to repair the recoil entirely before proceeding.

When comparing breaking down the recoil assembly and repairing broken parts with the cost of a new one, it may be more cost-effective to simply replace the whole thing.

Self-propelled mower with a faulty fuel cap

The fuel cap on your vehicle has openings in it that let air circulate. If the cap’s vent gets blocked, the gasoline tank cannot vent, creating a vacuum that prevents fuel from evaporating.

Try operating the mower with and without the gasoline cap. The gasoline cap may not be able to vent properly if the engine runs without it but dies after being put back on. Get a replacement fuel cap for your lawn mower.

Electric Starter On Your Self-Propelled Mower Has Stopped Working Due To A Blown Fuse Or Dead Battery.

There is a chance that the battery in your self-propelled mower won’t work if it relies on an electric start. Using the manual recoil, see if you can get your mower going. If you have to use the recoil to get the mower going, the electric starter is malfunctioning.

Battery life should be checked. A normal wall outlet can be used to charge the batteries of some mowers. Others will make use of a battery charger.

The fuses should be checked if the battery is not charging. Switch out the batteries if the fuses check out. If your self-propelled mower still won’t charge, you should take it to a professional mechanic for further diagnosis.

Auto-Faulty Mower’s Electric-Start Ignition Switch

That ignition switch might be broken. In the event of a negative test, you can simply swap it out.

Electric-Start Self-Propelled Mower has a Faulty Starter Solenoid.

The electromagnetic solenoid in a self-propelled mower functions as an on/off switch, activating the starter motor to crank the engine.

You should check the solenoid if you notice a click, hum, or smoking coming from the solenoid’s wires whenever you turn the key in the ignition.

Here are some instructions on how to test your solenoid. If you discover a faulty starter solenoid, you should replace it immediately.