Why Your Lawn Mower Won’t Turn Over With New Battery

When you get new parts for your lawn mower, the expectation is that it will perform better than before. However, at times this is not the case.

For instance, you might get a new battery for your lawn mower, but it won’t turn over. It is frustrating as your mower won’t start, rendering it useless. So, why won’t a lawn mower turn over ? A lawn mower won’t turn over with new battery due to a bad spark plug, a broken crankshaft, faulty electrical connections, damaged engine components, poor-quality fuel, or a faulty starter.

Let us look at mower turnover problems in detail and how to deal with them.

What Does Turning Over Mean?

Starting the engine vs. turning over, what is the difference? Starting refers to sending the electric current to the spark plugs to initiate ignition. Turning over is the driving of the crankshaft or the entire mechanical process of the engine. 

When you turn the key in the mower’s ignition, it turns on the starter. The starter motor subsequently moves the flywheel, which turns the crankshaft. You can now grasp the relationship between starting and turning over the engine.

Understanding the difference between the two terms will help diagnose several problems affecting your lawn mower. If the mower fails to turn over, most of the time, it is an issue to do with the electrical connections, mainly the battery. However, with a new battery, you should check out other components of the electrical unit and other parts. 

5 Reasons For Lawn Mower Not Turning Over

The following are possible explanations of why your riding lawn mower won’t turn over and the fixes.

Broken or Weak Electrical Connections

Start by checking on electrical connections, as they may be the culprit behind your mower’s problems. Corroded or sulfate-covered wires can affect the current flow, and the mower might fail to start. Clean the terminals using sandpaper to eliminate the stubborn sulfate buildup. 

Inspect the wires to see if they are okay. If broken, you can use duct tape to strengthen the loose parts. Once connected, the terminals should not wiggle. Wiggling calls for tightening of the bolts. Consider getting stainless steel bolts, which are resistant to corrosion.

Faulty Spark Plugs

The other reason a lawn mower won’t turn over with new battery might be due to bad spark plugs. Telltale signs of malfunctioning spark plugs include:

  • Acceleration problems.
  • A loud and misfiring engine.
  • Poor fuel economy and rough idling.

It is advisable to regularly change your lawn mower spark plugs, at least after every 25 hours of use or every season. Also, go for high-quality plugs for the best service.

Starter Problems

Starter problems may be due to a faulty assembly, with the starter solenoid and relay being the primary victims. Troubleshooting the situation calls for testing the starter. The typical sign of a bad starter is the mower failing to start with no crank. 

You should test the battery’s voltage before bringing an external power unit and a multimeter to check its continuity. Lack of continuity indicates a faulty solenoid. Alternatively, you may test the solenoid by bypassing it. 

Furthermore, you should probe the starter motor and its connections. A burnt-out motor won’t turn the flywheel; thus, no cranking. You can get a new motor or an entire starter assembly replacement for efficiency.

Replacement is the best solution for a faulty starter. While you may make minor repairs, they are temporary, and the problem can recur. 

Damaged Engine Parts

A lawn mower’s engine is prone to several problems, such as damaged components affecting its performance. A broken flywheel is one of the causes of why the lawn mower won’t turn over with new battery.

Most of the time, the snag is missing teeth, making engagement to the starter motor problematic. The mower may fail to crank, or starting may be difficult. Replacement is the most suitable solution for a damaged flywheel.

A dirty air filter is another culprit behind engine starting issues. Symptoms of a dirty air filter include power loss, black smoke emission, and poor fuel economy. Clean the air filter after every 25 hours of use, and get a new paper filter after 300 service hours. 

A bent or broken crankshaft can also affect turning over. With a bad crankshaft, starting can be challenging, and the mower will shake during operation. You may notice bad cuts when tending to your yard. You can straighten a bent crankshaft or weld it if broken. Get a replacement if the damage is severe.

Issues With the Fuel System

Do you have enough fuel in the tank, and is it of the right quality? This is a question to ask yourself when your riding lawn mower won’t turn over. Your lawn mower will stall if the fuel tank is empty. Low-quality and contaminated fuel will wear the engine, presenting starting issues in the long run.

If you used the wrong or poor-quality fuel, a fuel line flush would alleviate the problem. A clogged fuel line will also present cranking hitches. The blockage may be due to debris or frozen fuel. Flushing or using a vacuum pump will eliminate the debris. For frozen fuel, add more gas or diesel or pack the mower in a warm place.

A dirty fuel filter can bring about the cranking issue, even with a new battery. Clean this component or get a new one if necessary. Check the fuel shut-off valve. If locked, open it for fuel to reach the engine.

Final Thoughts

Getting a new battery relieves many mower owners, especially if they suspect a bad battery is the root of some issues. It may catch you by surprise to learn that the lawn mower won’t turn over with new battery.

Most of the time, the electric unit is the culprit. The focus should be on the wires, connections, and parts like the starter. Check the electric system and address any hitch. Inspect the engine for broken parts, primarily the starter motor, flywheel, and crankshaft. Repair and replace the parts where necessary, and enjoy your mower’s performance with a new battery.