Murray 91846MA Key Switch for Lawn Mowers

1. Introduction

This manual provides essential information for the proper installation, operation, and maintenance of your Murray 91846MA Key Switch. This key switch is a genuine Murray replacement part designed for use in various lawn mower models. Please read this manual thoroughly before attempting any installation or repair to ensure safe and correct usage.

2. Product Overview

The Murray 91846MA Key Switch is a critical component in your lawn mower's ignition system. It controls the electrical circuit that allows the engine to start and stop. This switch features multiple terminals for electrical connections, ensuring proper functionality within the mower's wiring harness.

Figure 1: Murray 91846MA Key Switch. This image displays the cylindrical metal body of the key switch with a beige plastic base. Protruding from the base are several copper-colored posts and silver spade terminals, designed for electrical wiring connections within a lawn mower's ignition system.

3. Compatibility

This Murray 91846MA Key Switch is a direct replacement for the following Murray part numbers:

• Murray 91846
• Murray 300687

Always verify the part number required for your specific lawn mower model before purchasing and installing.

4. Safety Information

Before performing any work on your lawn mower, observe the following safety precautions:

• Disconnect the Battery: Always disconnect the negative (-) battery cable before working on electrical components to prevent accidental starting or electrical shock.
• Remove Spark Plug Wire: For additional safety, remove the spark plug wire to prevent the engine from accidentally starting.
• Wear Protective Gear: Use appropriate personal protective equipment, such as gloves and eye protection.
• Consult Your Mower's Manual: Refer to your lawn mower's specific owner's manual for detailed safety instructions and wiring diagrams.
• Professional Assistance: If you are unsure about any step, consult a qualified service technician.

5. Installation

Follow these steps to replace the key switch:

1. Prepare the Mower: Ensure the lawn mower is turned off, the engine is cool, and the spark plug wire is disconnected. Disconnect the negative (-) battery terminal.
2. Locate the Existing Key Switch: Identify the current key switch on your mower's control panel.
3. Document Wiring: Before disconnecting any wires, carefully note or photograph the position and color of each wire connected to the existing key switch terminals. This is crucial for correct reinstallation.
4. Disconnect Wires: Carefully remove each wire from the terminals of the old key switch. Use appropriate tools if terminals are tight.
5. Remove Old Switch: Depending on your mower model, the switch may be held in place by a retaining nut, clips, or screws. Remove these fasteners and carefully extract the old key switch from the control panel.
6. Install New Switch: Insert the new Murray 91846MA Key Switch into the opening on the control panel. Secure it with the retaining nut, clips, or screws, ensuring it is firmly seated.
7. Connect Wires: Refer to your documentation (notes or photos) and connect each wire to the corresponding terminal on the new key switch. Ensure all connections are secure and tight.
8. Reconnect Battery and Spark Plug: Reconnect the negative (-) battery cable and the spark plug wire.
9. Test Functionality: Insert the key and attempt to start the mower to verify the new switch is functioning correctly. If the mower does not start or exhibits unusual behavior, recheck all wiring connections.

6. Operating

Once installed, the key switch operates as follows:

• OFF Position: The engine is off, and the ignition circuit is open.
• ON/RUN Position: The ignition circuit is closed, allowing the engine to run.
• START Position: Momentarily engages the starter motor to crank the engine. The key will spring back to the ON/RUN position once released.

Always ensure the key is fully inserted and turned to the correct position for the desired operation.

7. Maintenance

The Murray 91846MA Key Switch is a sealed unit and generally requires no routine maintenance. However, to ensure its longevity and reliable operation:

• Keep Clean: Periodically clean the exterior of the switch and surrounding area to prevent dirt and debris buildup.
• Inspect Connections: During routine mower maintenance, visually inspect the wiring connections to the key switch for any signs of corrosion, looseness, or damage.
• Avoid Force: Do not force the key when turning the switch. If the key is stiff, check for obstructions or damage to the key or switch mechanism.

8. Troubleshooting

If you experience issues after installing the new key switch, consider the following:

• Mower Does Not Start:
  • Check battery connections and charge level.
  • Verify all wires are securely connected to the correct terminals on the key switch.
  • Ensure the spark plug wire is properly connected.
  • Confirm the key is fully inserted and turned to the START position.
• Engine Cranks but Does Not Start:
  • This may indicate an issue beyond the key switch, such as fuel delivery or spark plug problems.
• Key is Stiff or Hard to Turn:
  • Ensure the key is not bent or damaged.
  • Check for debris around the keyhole.

If troubleshooting steps do not resolve the issue, consult your mower's service manual or a qualified technician.

9. Specifications

10. Warranty and Support

For warranty information regarding your Murray 91846MA Key Switch, please refer to the original purchase documentation or contact the seller directly. As a genuine Murray part, it typically adheres to the manufacturer's standard warranty policies for replacement components.

For technical support or further assistance, please contact Murray customer service or an authorized Murray service center. Always have your mower's model and serial number, along with the key switch part number (91846MA), ready when seeking support.