You're all set to mow the lawn, but when you go to start your machine, nothing happens. There could be several reasons why your lawn mower will not start, including something as simple as skipping a step in the starting process. Plus, depending on whether you have a walk-behind or riding lawn mower that won't start, you could have a different root cause for the same problem. Here are some troubleshooting tips to find out what went wrong, what lawn mower parts you need to fix it, and if you'll need to take your lawn mower in for professional service.
It seems simple, but sometimes you just forgot a step in the process. Before doing anything else, download the MTD operator's manual for your model and go through the steps to start your mower up again. You may need to engage the control handle, connect the spark plug wire, check the battery, and activate the choke and parking brake if you have a riding lawn mower. If your lawn mower still will not start, move on to the next step below. Keep that operator's manual close by as you will use it to identify any replacement lawn mower parts you need.
After a few years your spark plugs will have accumulated too much dirt and deposits to function properly, and the buildup on the electrodes can prevent a spark. If the damage or buildup is not too bad, you may be able to clean the plug. Otherwise, if it has become corroded beyond repair you'll need to replace it. You may also simply have a problem with the gap between your spark plugs. Check your operator's manual for the proper distance and adjust it.
When you mow, dirt and debris gets sucked up into your machine. That's why there's an air filter on it. But if your filter has become full and dirty, the debris may also work its way into the engine and your lawn mower will not start. Clean or replace the dirty air filter and change out the contaminated fuel. If you have a push or walk-behind mower, you want to be careful when changing out the fuel not to tip the mower on its air filter side as this can cause oil to leak into and clog the filter.
If none of the above tactics work, you can check out our tool to diagnose and troubleshoot your mower or take it in for lawn mower maintenance at a local service dealer. One of the last possible reasons for a lawn mower that will not start is a failed engine ignition coil. It's rare and you'll need to test for electrical activity with a spark plug circuit-testing tool. This lets you safely check the flow of the electrical current from the ignition coil to the spark plug terminal. If there's no electric activity, you'll need to take it to a professional for inspection and repair.