Mower won't turn over unless spark plug is out

By Dianne Catapang Written by Dianne Catapang
Updated on June 6, 2022

Maintaining the appearance of the yard is an important aspect of homeownership. That is why purchasing a good mower is a wise investment. But like any other machinery, mowers are prone to some issues.

Mowers are sometimes fragile, but things happen if you don’t check them frequently. Check the spark plug, battery, gas tank, and engine. Of course, you can fix this one yourself.

Mower won't turn over unless spark plug is out

Below are some of the most important things to troubleshoot a defective mower.

What would cause a lawnmower to not turn over?

It is necessary to check on your machines before working again with them. In this case, after picking up the lawnmower, it didn’t start, but why?

Make sure you have sufficiently new gas first. Problems with unmaintained gas can also matter. If your lawnmower still has the old gas stuck, drain it and replace it with new and fresh gas.

You should also check whether the spark plug is connected or not in your lawnmower. Sometimes the issues are they being loose or dirty at some point. Check them out, reconnect them, tighten them up, and clean them to work again.

Check the fuel if it reaches through the engine. If not, check and tap the carburetor to help it flow again (check sides too!) If this one still doesn’t work, a new gasoline filter may be required.

Possible causes of riding mower won’t turn over unless spark plug is out

The mower will not start because you’re not using the right spark plug. It is also notable that your mower may not start due to a fouled spark plug or it is being dirty.

You may notice that your spark plug is also outdated. If your mower still doesn’t start after cleaning it or plugging it in and out, make sure you’re utilizing the right substitute spark plug for the mower.

If the spark plug looks to be properly installed, but the engine still won’t start, a new one might be necessary. This simple fix will have your little engine up and running again, costing you only a couple of dollars.

Possible Solution: check if the starter is dragging

Bypassing the secondary current during a starter drag, you can determine whether the fault is with the cable or with the starter.

Mower won't turn over unless spark plug is out

Loose connections do not generate starter drag. If that were the case, the comparatively modest surface area would quickly heat up. Either that starter or the cables are defective. Jump both battery connections using a set of jumper cables to identify the starter if bad.

The starter is defective if both jumps fail to halt the dragging during cranking. Electricity always takes the shortest route. The starter would normally engage if the drag caused a voltage drop (high resistance) in this cable. Replace the cable.

The voltage drop issue occurs across both cables, which is unusual. Making these jumps will only alleviate some of the drag in that instance. If you can kill your ignition during these jumper checks, you should. That’s it.

Possible Solution: make adjustments to the exhaust valve

Mower’s engine consists of two valves, the intake and exhaust valve. If either valve is too loose, it will not work well. A feeler gauge should set the exhaust valve between 5 and 7 thousand (the most frequent setting is 4 to 6).

Tighten the center while holding the nut. It would help if you accomplished this on the compression stroke for the intake by closing the valve when it comes to closing the exhaust valve.

Make sure to adjust it to the right measurement because if not, it will be loose for sure. So checking the valves is important because they’re responsible for allowing the air into the engine and, at the same time, exhaust gas out of the engine of the mower.

Possible Solution: clean the mower’s deck

When the mower’s deck has accumulated too much grass clipping, it can cause the machine to malfunction.

Once it feels hard to pull, don’t force it, and turn off the mower immediately. Flip it over and if you see a gob of grass clippings confined between the blades and deck, brush them off using a trowel.

Possible Solution: check battery condition

Sometimes, the only problem why a mower doesn’t start is its drained battery. Not only being drained but also dirty and outdated. To make sure your mower won’t get any problems with batteries, clean them, replace if old, and put them tightly in its place.

Mower won't turn over unless spark plug is out

There are two common battery voltages available: 6V and 12V. Mowers batteries are 6V. Make sure to put a 6V battery on your mower to work without issues.

An outdated battery needs to be replaced. If you want it to work correctly, replace the old battery with the most recent and new battery.