HZ Ignition Coil Instruction Manual

Introduction

The HZ Ignition Coil is a replacement component designed for specific Briggs & Stratton L-Head engines. This coil is crucial for generating the high voltage required to ignite the fuel-air mixture in your engine, ensuring proper starting and consistent running performance. This manual provides essential information for installation, operation, and maintenance.

Setup and Installation

This ignition coil is compatible with Briggs & Stratton 16HP, 17HP, 18HP, 19HP, 19.5HP, 20HP, 20.5HP, 21HP Horizontal & Vertical Twin L-Head engines. It replaces OEM part numbers 590781, 392329, 394891, 394988, and 394895. It also fits various MTD, Troy-Bilt, Cub Cadet, and Craftsman riding mowers and tractors equipped with these Briggs & Stratton engines.

Installation Steps:

1. Safety First: Before beginning any work, ensure the engine is off and cool. Disconnect the spark plug wires and the battery's negative terminal to prevent accidental starting.
2. Locate and Remove Old Coil: Identify the existing ignition coil. Typically, it is mounted near the flywheel. Disconnect the kill wire and spark plug wires from the old coil. Unbolt and carefully remove the old coil.
3. Install New Coil: Position the new HZ ignition coil in the same location as the old one. Ensure the side marked "CYL SIDE" (or similar cylinder-facing indicator) is oriented correctly towards the engine cylinder.
4. Set Air Gap: A critical step is to set the proper air gap between the ignition coil's laminations and the flywheel magnets. Use a non-magnetic feeler gauge (typically 0.010 to 0.014 inches, refer to your engine's specific service manual for exact specifications) between the coil and the flywheel. Loosen the coil mounting bolts slightly, push the coil firmly against the feeler gauge and flywheel, then tighten the mounting bolts. Remove the feeler gauge.
5. Connect Wires: Reconnect the kill wire to the appropriate terminal on the new coil. You may need to re-use your old spark plug boots. Apply a small amount of dielectric grease or dish soap to the spark plug wire ends to ease insertion into the old boots if necessary. Ensure a secure connection.
6. Final Checks: Double-check all connections and ensure no tools or debris are left near moving parts. Reconnect the battery's negative terminal.
7. Test: Attempt to start the engine to verify proper installation and function.

Figure 1: General view of the HZ Ignition Coil.

Figure 2: Ignition coil showing the 'CYL SIDE' marking, indicating the side that should face the engine cylinder.

Figure 3: Ignition coil showing the 'THIS SIDE OUT' marking, indicating the outward-facing side.

Figure 4: Close-up of the spark plug wire ends, which may require re-using existing spark plug boots.

Operating Instructions

Once correctly installed, the HZ Ignition Coil operates automatically as an integral part of your engine's ignition system. No user intervention is required for its operation. The coil works in conjunction with the flywheel magnets to generate the necessary spark for combustion.

Maintenance

The HZ Ignition Coil is designed for durability and typically requires minimal maintenance. However, regular inspection can help ensure its longevity and optimal performance:

• Visual Inspection: Periodically inspect the coil and its wiring for any signs of physical damage, cracks, fraying, or corrosion.
• Connection Check: Ensure all electrical connections, including the kill wire and spark plug wires, are secure and free from corrosion.
• Cleanliness: Keep the area around the ignition coil clean and free of debris, oil, or excessive dirt, which can affect its performance and heat dissipation.

Troubleshooting

If you experience issues after installing the HZ Ignition Coil, consider the following troubleshooting steps:

• Engine Not Starting / No Spark:
  • Verify all wire connections are secure.
  • Check the air gap between the coil and the flywheel. An incorrect gap can lead to weak or no spark.
  • Inspect spark plugs for fouling or damage.
  • Ensure the kill wire is not grounded prematurely.
• Engine Stalls When Hot: This can be a symptom of a failing ignition coil. If the engine starts and runs when cold but stalls after warming up, and does not restart until cooled, the coil may be failing under heat.
• Weak or Intermittent Spark: This can indicate an improper air gap, faulty wiring, or a defective coil. Recheck the air gap and all connections.
• Hard Starting: If the engine is difficult to start, especially after sitting, a weak spark from the ignition system could be a contributing factor.

If these steps do not resolve the issue, it is recommended to consult a qualified engine technician.

Specifications

Warranty Information

Specific warranty details for the HZ Ignition Coil are not provided in this manual. Please refer to the retailer or manufacturer's official website for comprehensive warranty terms and conditions.

Customer Support

For technical assistance, installation questions, or further inquiries regarding your HZ Ignition Coil, please contact your retailer or the manufacturer directly through their official support channels. Have your product model number (BS105) and any relevant engine information ready when contacting support.