Lawn Mower Will Not Start

Written by Irene Melton | Updated
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If you have been using a lawn mower for more than one season then this would be a problem that you are most likely to face.

Typically lack of maintenance at the end of last season is the main reason for the problem this season. Here are some of the common reasons why lawn mower will not start.

There are many things that could lead to the mower not starting.

Clogged or stuck blade or crank system

One of the common issues could be a clogged or stuck blade or crank system.

If you have a rope start mower, you can also pull the rope and check if the crankshaft and the blades are moving properly. Once that is certain, you know that the problem is really with the mower engine.

Remember that with the recoil start mowers, the length of the rope needs to be long enough.

Without a long enough rope you will not be able to impart enough rotations to the shaft to get the engine roaring.

If you have an electric start mower, check if your spark plug is working fine and also if you have enough power in the battery to start the engine.

Sometimes you see that the engine starts but the parts of the mower do not grip and start moving. This would mean that you have disengaged the shaft or the gear box is broken.

Starting technique

If you are certain that it is not any of these things, then you need to start looking at other reasons why the lawn mower will not start.

Typically, each mower has its own unique starting technique. You need to know this well before experimenting with the starting procedure.

The simplest thing to do would be read the manual – as boring as it sounds that is your best guide to starting your mower properly.

There are some mowers that require priming before they will start properly. While there are some standard number of times you need to prime, if the weather is cooler, you may need to prime a bit more.

But make sure that you do not over prime and that can be detrimental too.

Old Fuel

The next thing to check is if your fuel is old.

Typically, people who do not carry out proper mower maintenance run into this problem and their Lawn mower will not start. This is common when people are too lazy to clean their lawn mowers and empty the fuel tanks at the end of the fall season.

The old fuel can really cause major starting problems. In such cases, if you missed cleaning the mower at the end of the season, you can compensate that by cleaning it at the beginning of the season. This is a one-time effort that can give you a peaceful mowing experience for the rest of the season.

There are times when the fuel injection system is clogged and as a result of that there isn’t enough fuel being injected into the cylinder.

You need to clean the injection system to get the engine roaring again.

Problems with the air intake system too can cause engine starting problems. Ensure that the air intake system is clear and does not have any clogging.

If there is less air in the cylinder, you will burn the fuel inefficiently and there would be smoke coming out of the engine.

If the air inlet valve is not too wide, too much air will flow into the system. This will dilute the fuel and this will also lead to problems.

Spark Plug

Lastly, if you have everything else sorted out, then the problem could be with the spark plug.Sometimes the spark plug is defective or has just worn out with time. You need to replace such spark plugs.

Sometimes the battery powering the spark plug is too weak to generate enough spark to ignite the engine. The electrical wiring of the system too could be faulty causing loose connection. So check the entire electrical system of the mower to ensure that is working properly.

Lawn Mower Blades

In a rare instance, if the blades of a mower in motion hit some immovable object you could end up with a bent crankshaft and that would mean that your mower would not function at all. Replacing the crankshaft is the only solution in that case.