How to test a lawnmower solenoid

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One fine day you plan to cut your lawn, but as soon as you start your lawnmower, nothing happens. After some checking, you think that the problem is either with the battery or the lawnmower’s solenoid. But you don’t want to take the lawnmower to a mechanic who might charge you a lot for testing the solenoid. This blog will help you how to test and replace your lawnmower’s solenoid and replace it if it’s faulty.

Lawnmower solenoid is usually located at the bottom left side of the vehicle below the battery. It’s attached to the lawnmower’s metal body via screws. The solenoid may often deteriorate as it’s service life may end, or it’s terminals may get damaged due to corrosion. The solenoid may be a 3-post solenoid or a 4-post solenoid. The testing methods used to test these solenoids are the same.

How to test a lawnmower solenoid and replace it:

  • Step 1: Remove the solenoid from the lawnmower
  • Step 2: Test the solenoid using a multimeter and a 12V battery source
  • Step 3: Purchase a new solenoid if the test fails
  • Step 4: Install a new solenoid
  • Step 5: Test the lawnmower with the new solenoid

We shall provide in-depth details of the steps mentioned above in the section below, like what sort of equipment to use for the testing, how to make the solenoid connections. Stay tuned to this article, as we are here to get your problem solved without wasting any time.

Steps to Test Lawn Mower Solenoid:

The procedure below explains all the necessary steps to test the solenoid and replace it with a new one if worn out to ensure that the lawnmower goes up and running again.

● Step 1. Removing the solenoid from the lawnmower:

The lawnmower solenoid may get defective with time because its terminals may get rusty due to moisture present in the air, or the metal plate inside the solenoid may have stopped working. To check the root cause of the solenoid’s malfunctioning, it must be removed from the lawnmower first.

– Step I: Removing the battery from the lawnmower:

The solenoid is usually located below the battery, on the bottom left of the mower. Firstly, turn the ignition switch off and remove the key. Now, lift the seat and remove the negative terminal from the battery. Similarly, remove the positive terminal from the battery. Take the battery out of the battery box and release the seat switch wire clip from the seat bracket. Next, remove the retaining tabs and lift the battery box out of the mower’s body.

– Step II: Removing the solenoid from the lawnmower:

You shall see a solenoid now, attached to the lawn mower’s metal body via some screws. Remove the wires connected to the terminals of the solenoid. Also, pull the wires from the coil spades. Next, remove the starter solenoid mounting bolt from the mower’s frame. Rotate the starter solenoid forward and pull it out from the lawnmower. Taking a good photo from your phone before removing the solenoid’s connections is also a great option so that it may help you reconnect the solenoid correctly.

Since the solenoid has been detached, now it’s time to test it.

● Step 2. Test the solenoid using a multimeter and as 12V battery source:

The testing method is carried out by using a 12V battery source and a multimeter. The testing methods for the 3-post and the 4-post solenoid are the same, so no need to worry about that!

– Step I: The “click sound” test using a 12 V battery:

To carry out this test, you first need to connect the available battery’s negative terminal to the solenoid’s negative. If the solenoid is a 3-post solenoid, no separate connection is available to attach the battery’s negative terminal. In this case, the battery’s negative is connected to the metallic screw plate of the 3-post solenoid. However, in a 4-post solenoid, a separate connection is available on the solenoid, where the battery’s negative terminal is attached.

Now, when the negative terminal has been connected, as soon as the battery’s positive terminal is connected to the solenoid’s positive connection, a “click sound” shall be heard by the person performing the test. If there is no sound, it means that the solenoid is faulty and replaced with a new one.

– Step II: The connectivity test using a multimeter:

If the solenoid passes the click sound test, the next test is the connectivity test. For this, you first need to make the positive and negative connections as mentioned above. Then the multimeter should be switched to the connectivity test/beep test mode. The multimeter’s positive and negative terminals should be connected to the two main terminals present on the solenoid’s uppermost part. If the multimeter gives a beep sound, it means that the solenoid is perfectly fine and doesn’t need to be replaced.

But if there is no beep sound, it means that the solenoid has failed the beep test and must be replaced by a new one.

● Step 3. Purchasing a new solenoid:

Now, as you have witnessed the test failure on the solenoid, you finally decide that the only option now is to buy a new one and throw the old one away! In doing so, you should take care that the new solenoid being purchased should be the same as the one being replaced. The critical thing to be kept in mind is whether the old solenoid was 3-post or 4-post, and so the purchase should be made accordingly. Consulting the lawnmower’s user’s manual is also a good option in this process. During the purchase, always ask the seller to provide you the solenoid according to your particular model.

● Step 4. Install the new solenoid:

Are you tired after going through such a long process of testing and shopping? Don’t worry. You are almost at the point where your lawnmower gets up and running again. Just one more last step, and that is to install the new solenoid into the lawnmower.

– Step I: Making the connections with the new solenoid:

First of all, make sure that the ignition switch is off and the key has been removed. Transfer the mounting clip from the old starter solenoid to the new one. Position the new starter solenoid on the lawnmower’s frame and install the mounting bolt. Connect the wires to the coil spades. Next, install the wires on the terminal posts, connecting them with the mounting nuts. The new solenoid has now been installed successfully.

– Step II: Installing the battery back into the lawnmower:

Position the battery box in the opening and engage the retaining tabs. Now reconnect the seat switch clip to the seat bracket. Lower the battery into the battery box and align the battery cables. Reconnect the negative battery cable to the battery’s negative and the positive battery cable to its positive terminal. Put the insulating cover back in place. Lower the seat, and you are ready to test the lawnmower now!

● Step 5. Test the lawnmower with the new solenoid:

After all the day’s hustle, why not test the lawnmower and take it for a spin on your garden. Put the key back in and turn the ignition switch. Guess what? The lawnmower has started and is buzzing like it’s a new one! You can enjoy your day and make your garden even more beautiful.

For a hands-on demonstration of how to test a solenoid, you should watch this video:

Related Questions:

1) The solenoid has passed the testing phase, but still, my lawnmower won’t start?

There are a few possibilities that cause this problem. But we are here to help you with it. Here are a few reasons why the lawnmower won’t start despite the solenoid being perfectly fine:

A. Battery: The lawnmower battery might be dead. To check either this is the issue, connect your multimeter to measure the voltage across the battery. Suppose the voltage across the battery is considerably less than 12 volts. In that case, the battery is dead, and you need to charge it with another battery or a battery booster.

B. The Cable: The cable connecting the solenoid to the starter in the engine may be worn out and may not supply voltage to the starter. So, to resolve this issue, move your multimeter to continuity mode and place the multimeter terminals on each end of this wire. If a beep sound isn’t produced, it means that the wire is faulty and needs to be replaced.

2) The solenoid is requiring a replacement every month. What shall I do?

Usually, a solenoid may do its work perfectly fine for some years before it requires a replacement. The solenoid requires a replacement because maybe the ground connection being provided to it isn’t strong enough because of some debris or dirt. Make sure that the metal on which the solenoid is being mounted has a firm ground. Remove the solenoid and use sandpaper to clean up the metal area. The solenoid is being mounted to get good contact.

Final Remarks:

If you love your garden and gardening absolutely boosts your mood on a bad day, then the lawnmower must be maintained and well cared for. It isn’t enjoyable when you turn your lawnmower’s key, but it won’t start. But the lawnmower’s solenoid can now easily be removed, tested, replaced, and reinstalled at your home by reading this article. Your safety is also our topmost priority, so don’t forget to take certain precautions while performing the testing process. You must always wear work gloves before starting the process to protect you from unnecessary cuts. Besides, the wrench set and other tools must be used with great care and kept out of children’s reach. Also, don’t forget to perform timely maintenance of the lawnmower’s other parts such as filters, cutting blades, oil well.