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How to jump a solenoid on a lawnmower, step by step

Sometimes the Lawnmower might be taking agitated starts and maybe not completely start on the flip of your key. You have just gone through all the tests, and all major components such as sparkplugs, ignition coil, carburetor, fuel supply, and lubrication system are working fine. But the mower is still not starting. Further diagnosis points to two possible causes, a faulty starter motor or a bad solenoid. One more thing worth mentioning is that a completely discharged or old disintegrated battery might also be the cause.

How to jump a solenoid on a lawnmower, step by step

  • Step 1: Turn the ignition switch on
  • Step 2: Locate the lawnmower solenoid
  • Step 3: Find the relevant terminals
  • Step 4: Clean the carbon and rust deposits from the terminal
  • Step 5: Jump the solenoid

Before learning to jump the solenoid, it is important to go through the various diagnosis steps. Understanding the working of the circuitry helps with this.


Diagnosing the lawnmower problem

Before starting with jumping the solenoid, it is a good idea to diagnose your lawnmower problem to ensure that you fix the real problem. Jumping the solenoid is easy and quick. But to do it correctly, it is important to understand why and what you are doing. The main starting circuit consists of different switches, a key, a solenoid, a starter motor geared to the engine flywheel, and a battery to power these all up.

  • Switches: Sensors ensure all safety requirements are met before the Lawnmower can be started. For example, the brake switch ensures that the brake is engaged and the Lawnmower is in parking mode.
  • Starter Key or button: With the key or button, the Lawnmower can be started. It has the indication of ON and Power on it. It allows the current from battery to solenoid and from solenoid to starter motor.
  • Solenoid: An electromagnet present after the battery relays the current flow from the battery to the starter motor. A click sound is generally noticed when the solenoid engages.
  • Starter motor: When we need to start the Lawnmower, the engine needs an initial push to intake air and gas and get to its first spark. This action is performed by the started motor geared to the flywheel or crankshaft of the engine.
  • Battery: It provides the potential difference to run all electrical components. Even the sparkplug and coil get energy from this battery.

The Lawnmower’s inability to start can be caused by one or more of these components malfunctioning. In short, directly, a solenoid cannot be blamed. To be clear on whether or not to jump a solenoid, the diagnosis part is important. If you want to be quick and already know the reasons, you might like to skip to the step-by-step guide.

  • Check the battery: Using a Digital Multimeter, check the battery’s voltage by connecting the multimeter’s with the battery’s positive and negative terminals. If the voltage from the battery is not 12 V or greater, the battery probably needs a recharge or replacement.
  • Connections and fuse: Turn the knob of DMM to continuity. Touch the connecting wires from battery to solenoid to starter motor and check the continuity. Check the fuse that is often present before the solenoid.
  • Solenoid check: Connect the solenoid to the ground and terminal of another battery and check the terminals’ continuity (the two large terminals on top of the solenoid). The clicking sound heard upon turning the start switch indicates a properly functioning solenoid. Jumping a solenoid is also a diagnostic procedure for solenoid health.
  • Starter motor: If a clicking sound is heard when the starting key is flipped, check the voltage of the motor terminals. If the voltage is good and the engine is not starting, the motor has probably failed. A whirring sound indicates that the gear from starting motor to the flywheel has worn out.

Suppose the diagnosis shows that the solenoid is malfunctioning and you do not have a spare one. The easiest and quickest way is to jump to the solenoid. There is no harm in this procedure because the solenoid is just a relay that allows momentary current to flow when required.

How to jump a solenoid on a Lawnmower, step-by-Step Guide:

Tools Needed:

These are a few basic things that will be required to carry out the jumping procedure.

  • Metal screwdriver
  • Sandpaper
  • Jumper cable
  • Digital Multimeter
  • Emergency Battery pack

• Step 1: Turn the ignition switch on

Turn the ignition key to the ON position. When you turn the key to start and hold, the engine tries to start but fails. This indicates poor solenoid or battery. 

• Step 2: Locate the lawnmower solenoid

  • Locate the battery: First, locate the battery either under the seat or under the hood.
  • Follow the wire: Track the wire from the positive terminal that ends up to a cylindrical structure with either 3 or 4 wires attached to it.
  • Solenoid: This cylindrical component is the starting solenoid.
  • Type of solenoid: The three-pole solenoid has a common ground and is connected to the mower’s body. The four-pole solenoid has a specific terminal for the ground as well. 

• Step 3: Find the relevant terminal

It is straightforward to find the copper post that connects the battery’s positive terminal to the starter motor’s positive terminal. These terminals are bigger compared to the positive and negative of the solenoid. And usually, the copper-brown color also indicates the ones that need to be jumped.

• Step 4: Clean the carbon and rust deposits from the terminal

  • Check the battery volts: It is important to check the battery before proceeding further. Use a Digital Multimeter to check if you measure above 12 Volt. If it is less the battery needs to be recharged first.
  • Clean the terminals: If the battery is good, use sandpaper to clean the solenoid’s terminals.
  • Enhance the accessibility: If the solenoid is not easily reachable, use the wrench set to remove it. Clean it and attached the jumper cable as an extension.
  • Reassemble: Place the solenoid back, keeping the extension accessible.  

• Step 5: Jump the solenoid

Using a metal piece, a metal screwdriver can do the job, connect the two copper posts. This needs to be done with the key in the “ON” position.

This should start the mower the same way as it was when you were using the key. Sparks will be produced when the jumping is performed. This is nothing to worry about. Continue the procedure until the Lawnmower starts (also with a key you have to try again sometimes).

Jumping the solenoid is not a complicated job, nor is it harmful to the Lawnmower’s health. This is a handy procedure that is good to know. It will help situations where you might have ordered a new coil and the shipment is delayed. Having knowledge on how to jump the coil will save you a lot of effort and time.

Precautionary measures

  • Safety Equipment: Where applicable use proper safety goggles, gloves, and the suit should be worn.
  • Keep distance from a flammable source: The jumping will often cause some sparks, so any flammable fluid should not be present nearby.
  • Battery recharge: If the battery needs to be charged, try to do it in an open or well-ventilated environment. Depending on the battery, some of the gases released during recharging can be harmful.
  • Insulation from Electric shock: Use proper insulated boots and gloves when you work near the spark plugs. Check the insulation of all wires. Use some insulation tape if you find damaged wires.

Related Questions

1. What does it indicate if the mower starts when the solenoid is jumped?

Suppose you had not performed the diagnostic already and wanted to save time. Upon jumping the solenoid, the mower starts. It indicates that the solenoid in the starter circuitry is not working correctly and need to be replaced.

2. What if the Lawnmower does not start even upon jumping the solenoid?

If jumping, the solenoid does not work. Check the motor, battery, and lose connections. In most cases, this will lead you to the culprit. Still, there is a chance that any of the connecting wires got damaged, and checking the continuity is the best idea.

3. What is the difference between a jump start and jumping a solenoid?

Jumpstart is generally used when the battery had died, and another battery pack is used to provide power. In that case, you can use the key to start the mower. However, if the battery is good and upon turning the key, the mower does not start. Rather than just puffs to start, jumping the solenoid is the remedy. This is connecting the starter motor directly to the battery.

4. What method should be used to clean the terminals?

Medium grit sandpaper is a good method to clean any corrosion and carbon deposits. A soft wire brush is also a good way to go. But beware that heavy abrasive processes such as grinding should not be used. The reason being, it can damage the threads, connectors, and also the solenoid itself.

Final Remarks

A solenoid is a basic component of the lawnmower starting system. Its poor performance can lead the owner to worry. If a proper diagnosis is performed and the root cause is the solenoid. If you do not have a spare, jumping is the easiest, most convenient, and time-saving way. The method is not only a solution to a problem but will also act as a confirmation, whether or not the solenoid is causing the failure. In case you do not know how to jump the solenoid, this blog will help you.

Understanding the Role of the Solenoid in Lawnmowers

When it comes to starting lawnmowers, the solenoid plays a very pivotal role. The solenoid is the component that bridges the gap between the battery and the engine.

It is responsible for transmitting current from the battery to the engine, which enables the lawnmower to start effectively. It is akin to a bridge, helping the power from the battery to reach the engine to ignite the lawnmower.

• Diagnosing Why a Lawnmower Only Starts When the Solenoid is Jumped

There are various reasons as to why a lawnmower might only start when the solenoid is jumped. Usually, this points towards some technical glitch. The most likely culprits behind this issue include a faulty solenoid, problems with the ignition system, and issues with the terminals or the control cable.

Michigan State University recommends systematic troubleshooting to narrow down the potential sources of the problem.

• How to Fix a Faulty Solenoid

Normally, when you encounter a faulty solenoid, the remedy is replacement rather than repair. Start by gently removing the cables that run to the solenoid. Next, take out the bolts that are holding the solenoid in place.

I recommend seeking professional help if you are not comfortable performing these steps, as incorrect removal can cause further damage to the lawnmower.

• Addressing Issues with a Faulty Ignition Switch

If the ignition system of your lawnmower is faulty, the best course of action is to replace the entire system. Remember, the ignition system is like the brain of the lawnmower. Thus, any malfunctioning part can significantly affect the entire system.

Replacing the entire system rather than a part ensures your lawnmower runs smoothly.

• Investigating a Faulty Control Cable

A faulty control cable can be another reason why the lawnmower may not be starting properly. Use a multimeter to check the voltage running through the cable. If the reading is lower than the lawnmower’s battery voltage, the control cable is faulty and needs to be replaced.

• Mending Broken Connections in Starter Circuit Terminals

A lawnmower might also experience starting problems due to broken connections in the starter circuit terminals. These broken connections can prevent the transmission of power from the battery to the engine through the solenoid.

In case of such issues, these connections need to be fixed. If there are loose terminals, they should be tightened and if there are broken connections, they should be repaired or replaced.

• Distinguishing Between Jumping the Solenoid and Jump-Starting a Lawnmower

Often, the terms ‘jumping the solenoid’ and ‘jump-starting a lawnmower’ are used interchangeably, albeit incorrectly. The two are not the same.

Jumping the solenoid is a temporary solution that is implemented when the solenoid itself is faulty. On the other hand, jump-starting a lawnmower is a measure taken when the mower’s battery is not working.

• Using the Temporary Solution of Jumping the Solenoid

While jumping the solenoid is a temporary solution to get your mower running, its not a long-term strategy. It’s crucial to identify and rectify the root problem causing your lawnmower troubles to prevent more complex future issues.

• Taking Appropriate Safety Precautions When Jump-Starting a Lawnmower

Safety should be your primary focus when performing any kind of maintenance on your lawnmower, let alone a jump-start. Always wear your protective gear and gloves to safeguard yourself.

Another integral part of safety ensures the voltage of the external battery matches with that of the lawnmower’s battery to prevent electrical shocks or other mishaps. Always refer to your manufacturer’s guidelines or the Consumer Product Safety Commission for more detailed safety precautions.

Your lawnmower is a crucial part of your household tools, so maintaining it in top shape should be a priority.

Understanding the different mechanisms and how to diagnose and troubleshoot common issues can save you a lot of time, money, and frustration. Take care of your lawnmower, and it will serve you for years to come.

Diagnosing Faulty Solenoid or Starter Motor

For any proficient mechanic or home automotive enthusiast, diagnosing a faulty solenoid or starter motor can often pose a significant challenge. This is because it is essential to consider other surrounding components, such as the battery and wiring, as the cause of the issue.

Overlooking these parts can lead to a misdiagnosis and time wasted messing around with a perfectly good solenoid or starter motor.

• Checking Battery Voltage

One of the first steps in diagnosing a faulty solenoid or starter motor should be to check the battery’s voltage. With the help of a Digital Multimeter, this procedure becomes an effortless task.

I recommend using a Digital Multimeter due to its accurate readings and ease of use, making the process straightforward and efficient.

Remember to set the Multimeter to 20 volts DC before taking any readings. The battery should register a reading of around 12.6 volts at the very least when fully charged. If the battery voltage reading is less than 12 volts, it could be the cause of the starting problem.

• Cleaning Solenoid Terminals

Neglected terminals are a common cause of problems that can confuse the unwary into thinking that the solenoid or starter motor is at fault. Therefore, cleaning the terminals of the solenoid should be the next point in line. The importance of removing carbon or rust deposits cannot be understated.

For safety purposes, you should disconnect the battery before cleaning. Simultaneously, the use of a wrench set might be vital in removing and cleaning the solenoid if it is not easily accessible.

During the cleaning process, special attention should be given to the cleaning agents used. Only use cleaning solutions suitable for electrical contacts and follow the manufacturer’s instructions accordingly.

• Jumping the Solenoid

Once the battery has been checked and the solenoid has been cleaned, you may look into jumping the solenoid if problems persist. This process can be risky if not done correctly.

Jumping the solenoid involves connecting the two copper posts with a metal screwdriver or similar tool while the ignition is in the “ON” position.

Do take care while doing so because sparks may fly during the process. However, this is a normal part of the procedure and doesn’t indicate any issues in and of itself. Needless to say, I shouldn’t have to remind you to wear safety glasses during this operation.

• Warnings and Safety

Remember to take safety precautions when dealing with electrical parts. Keep clear of heat and open flames as sparks from the ignition could ignite a fire. Protective gear, such as gloves and safety goggles, are recommended.

Most importantly, know your limits. If you’re not confident in diagnosing or repairing these components, take it to a professional.

I recommend checking out the Federal Trade Commission’s guide to auto repair basics for information on the process and instructions on when to consider professional help.

Ultimately, remember that no repair is worth putting yourself at unnecessary risk. Good luck, and safe repairs.

Identifying the Probable Cause of a Non-starting Lawnmower: Battery Considerations

Failure to start is a common issue in lawnmowers, which can often be attributed to a completely discharged or an old, disintegrated battery. The battery is a fundamental component, as it provides the potential difference needed to power all electrical components in the lawnmower.

Keep in mind the main starting circuit of a lawnmower encompasses several components, including switches, a key, a solenoid, a starter motor, and a battery. All these components must be in good condition for the lawnmower to work optimally.

• Role of Different Components in the Starting Circuit

Take note of the brake switch, a safety switch that ensures the lawnmower is in parking mode before it can be started. This is an essential feature as it prevents accidental starts that may lead to damage or injuries.

Another key component in lawnmower start-up is the solenoid, an electromagnet responsible for relaying the current flow from the battery to the starter motor. When you turn the key, it is the solenoid that takes charge.

The starter motor plays a critical role by giving the initial push to the engine. It allows the machine to intake air and gas to produce the first spark needed to turn on your lawnmower.

• Testing the Solenoid

To diagnose if the solenoid is functioning correctly, professionals often resort to a practice called ‘jumping the solenoid’. Pivotal to the success of this process are tools like a screwdriver, sandpaper, jumper cables, a digital multimeter, and an emergency battery pack.

Jumping the solenoid may sound complex, but it simply involves connecting the two copper posts of the solenoid with a metal screwdriver. This should be done while the ignition key is in the ‘ON’ position.

However, it’s crucial to take precautionary measures while jumping a solenoid. Always wear safety goggles and gloves and maintain a safe distance from flammable sources.

• Interpreting the Results

The results obtained from jumping the solenoid can be revealing. If the lawnmower starts, this implies that the solenoid, specifically within the starter circuitry, is malfunctioning and needs a replacement.

However, if the lawnmower doesn’t start even after jumping the solenoid, I recommend checking the motor, battery, and loose connections for potential issues.

Now, remember jumping a solenoid is different from jump-starting a lawnmower’s battery. Jump-starting involves using another battery pack to energize a dead battery while jumping a solenoid bypasses a malfunctioning solenoid directly.

• Cleaning and Maintenance Tips

For cleaning terminals, I recommend using medium grit sandpaper or a soft wire brush. Grinding or heavy abrasive processes can cause unnecessary damage and should be avoided.

• Diagnosing the Issue

Before jumping the solenoid, it is important to diagnose the root cause of the lawnmower’s starting issue. This will help confirm that the solenoid is indeed the problem.

Only after a thorough diagnostic analysis should one attempt to bypass or ‘jump’ the solenoid. This information is based on many years of experience in this field.

• How to Fix a Non-starting Lawnmower

If the problem remains unresolved after jumping the solenoid, some alternative solutions might include replacing a faulty ignition or control cable and cleaning corroded terminals.

For detailed instructions on replacing a worn-down solenoid, consult online manuals available on non-commercial websites like edu or .gov sites, such as the University of Arkansas, which offers free lawnmower maintenance resources.

Knowing how to jump-start a solenoid can save a lot of time and effort, especially when a replacement solenoid is not readily available. Professional or expert insights, like the one offered in this article, are a treasure trove of knowledge.

So, make sure to utilize them and always keep safety at the forefront of your mind when repairing your lawnmower.

Diagnosing Causes for a Non-Starting Mower

• Battery and Solenoid Replacement

The first stage of my troubleshooting was to replace the battery and solenoid. Given the nature of their role in the ignition process, they tend to wear out over time and might render the mower incapacitated.

However, after carrying out these replacements, the lawn mower still didn’t start when the battery was used.

• Proper Starting Procedure Followed

In situations like these, we must confirm that the right starting procedure is being followed. It may seem trivial, but it’s one of the most overlooked aspects when attempting to start a mower.

Despite meticulously adhering to the recommended procedure, there was still silence emanating from the mower. There were no clicking sounds – a clear indication of a thoroughly followed starting procedure.

• Testing Voltage Draw

To advance the troubleshooting process,, an esteemed .org site, suggests testing the voltage draw to detect potential issues.

It is an effective method that underlines the amount of electricity consumed by the mower when attempting to start. What it ratifies is that the lawn mower isn’t drawing enough power (or none at all) irrespective of the new battery.

• Jump-Starting the Mower

The method used to jump-start the mower could result in incorrect diagnosis. Hence, I recommend carefully choosing the right method that mirrors the mower’s specifications.

Notably, it necessitates understanding whether it requires direct current (DC) or alternating current (AC), as misuse could lead to further damage.

• Testing the Battery Externally

Out of probability or mere curio, I thought it would be prudent to test the battery externally. It ran through the paces at a store and was confirmed to be fully operational and efficient. This confirmation implies that the issue lies not with the battery but likely elsewhere within the mower.

• Further Diagnostics and Recommendations

Having established that the issue does not revolve around the battery, the solenoid, or the starting procedure, you may need to check the ignition system.

An inefficient ignition system might mean that even with a full battery, there won’t be adequate spark to initiate the starting process. Check the spark plug conditions and verify the timing.

Also, evaluate the mower’s electrical wiring. For an electric start lawnmower, a poorly connected wire or a short circuit can halt the starting process. Therefore, a thorough scan of the mower’s wiring could shed light on some unanticipated issues.

Ensure that you inspect the mower’s carburetor too. It’s a common but often overlooked cause of starting problems. A blocked or dirty carburetor can halt the start-up procedure, and a thorough clean might be all that’s needed.

Lastly, old or wrong fuel could also be a factor. If the fuel in the mower is old or of low quality, it could lead to difficulties in starting. Changing the fuel might be a simple solution to a non-starting mower.

In conclusion, diagnosing a non-starting lawn mower requires logical thinking and a systematic approach. By methodically eliminating possible causes, you can finally pinpoint the exact problem and resolve it.