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Mower Stops When Blades Are Engaged: Why and What to Do

Mower Stops When Blades Are Engaged: Why and What to Do

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Paul Brown

Here are a few possible reasons why your mower might stop when the blades are engaged!

The most common causes for a mower to stop when blades are engaged include the mower being in reverse, faulty safety switches, bad fuel, or clogged fuel lines. Trying to engage the blades in tall or wet grass can also cause the mower to die.

While fuel can be a common issue, it might not be your issue. Several other possible things might be wrong with your mower. Here are a few of them and some ways to fix/prevent them.

Common Issues

If you have started your lawnmower and it stops shortly afterward, check to make sure the mower gear is not in reverse. If you engage the blades and then try reversing the mower, it could and probably will shut off as a safety measure.

Faulty safety switches are another common issue. This is especially true with riding mowers. The seat usually has a safety switch that detects if there is a rider. If sufficient weight is not detected, the motor will die when blades are engaged.

These are the first things you should check. You probably do not want to go looking into more complicated and possibly expensive solutions if the fix is something as simple as reverse mode. Your troubles could be over that fast! If this is not the answer, don’t worry. There are still other possibilities!

As mentioned above, multiple issues could be plaguing your lawnmower, fuel being one of them. If moisture is getting to your gas tank, it might be causing your machine to sputter and stop, especially when the blades are engaged.

Your issue might also be a clogged fuel filter. An excessively dirty or clogged filter will impede the flow of fuel.

You might also need to inspect your spark plug. If it is worn out or damaged in any way, you will either need to clean it or replace it. If the firing end is covered in carbon, you can clean it off with a wire brush. If the spark plug is damaged, you will need to replace it.

Click Here To Learn How to Know if a Lawn Mower Spark Plug is Bad

The problem could also lay with the grass you are cutting and not necessarily the mower itself. If you are mowing in a particularly dense, grassy area, you might just need to change the height adjustment of your blades. I’ve bogged down my mower more times than I can count trying to work through tall grass. If you consistently try to mow grass that is too tall or too thick it could severely damage your mower.

The same is true if you are trying to mow excessively wet grass. Wet grass is much heavier than dry grass. The wet stuff will stick to the blades and will definitely add a few pounds to the lawnmower. This will put additional strain on the motor and could very well shut it off. Keep in mind that overworking the mower is one of the most common causes of it quitting while the blades are engaged.

Quick Fixes

Most of the aforementioned solutions can be quickly and easily solved. If diluted fuel is indeed the problem, your best bet is probably to drain the gas tank and start over. Dirty gas is equally damaging to the motor, which can cause it to quit. Emptying the gas tank is the best solution in this instance as well. Be sure to properly dispose of the gasoline when you are done doing this.

It might also be wise for you to replace the fuel filter. If it is clogged and dirty, it will not only cause your motor to quit, but will also prevent an adequate air supply from making it into the tank. Gas needs air to ignite, so that can definitely be a problem. If the problem lies with a leaky fuel line, you may or may not need to call a professional. If you are handy enough to fix it then great, but if not, you should probably seek help.

We have already discussed what to do if your spark plug is having problems. If you are not sure how to tell whether the plug is damaged, you can look for cracked or chipped porcelain housing or a rounded tip on the center electrode. Any of these things could mean you need to replace your spark plug.

Here’s How to Know if a Lawn Mower Spark Plug is Bad

You can also try replacing/fixing/cleaning the carburetor.

The carburetor’s job is to mix fuel and air that will help the mower run smoothly. The carburetor contains a series of needle valves, floats, springs, and spray jets. Any of those parts are susceptible to clogging or damage. Inspect the carburetor thoroughly for any damage. If it needs to be cleaned, you can do so on your own. If it is damaged and you are familiar with carburetor repair, have at it. If you are unsure of how to proceed, the wisest course of action you can take is to call a professional and have them help you out with repairs.

Maintenance and Preventative Measures

How to Tune Up a Lawn Mower

It can be frustrating to have to deal with any of the issues mentioned above. Believe it or not, you might be able to avoid some of these things by taking good care of your lawnmower. Regular and consistent maintenance can prevent you from needing to undergo any sort of repair or replacement.

Here are a few tips:

Lawnmower maintenance can be undertaken any time of year, really, but the ideal time is at the end of the mowing season. You can start taking good care of your mower by removing any sticks, rocks, or debris from your yard before mowing. This will keep the blades from getting damaged and the motor from quitting mid-cut. Try to avoid mowing when the grass is wet, and never mow in the dark.

Replacing the oil regularly will help to keep it from getting old and from damaging your engine (remember, running a mower with dirty oil is a no-no!). If you are ready to pack your mower up for the winter season, you ought to either empty the fuel tank or add a fuel stabilizer. This is generally good practice for whenever your mower will be idle for 30 days or longer.

Cleaning/replacing the air filter regularly will also help to keep your mower clean and healthy. In fact, giving the mower itself a hose down and scrub every once in a while isn’t a bad idea either. Keeping it clean will keep the oil reservoir and fuel tank clean as well. Finally, keep your mower blades sharpened and balanced. Doing so will ensure optimal performance!