Ignition Sensor Kit – Fits MerCruiser GM V6 & V8 with Thunderbolt IV & V Ignition (Replaces 87-91019A2)

Ignition Sensor Kit – Fits MerCruiser GM V6 & V8 with Thunderbolt IV & V Ignition (Replaces 87-91019A2)

This ignition sensor kit is designed for MerCruiser V6 & V8 engines (4.3L, 5.0L, 5.7L, 7.4L, 8.2L) equipped with Thunderbolt IV & V electronic ignition systems from 1981–1997. It serves as a direct replacement, ensuring reliable ignition performance for a wide range of popular marine engines.

Engineered for marine environments, this component provides a cost-effective solution for restoring your engine's ignition timing and performance. It directly replaces multiple OEM part numbers, including Mercury/MerCruiser 87-892150Q02, 87-91019A2, Sierra 18-5116-1, and Mallory 9-29804.

• Installation Method: Direct replacement for a straightforward installation.
• Durable Construction: Features a glass-filled polyester housing for enhanced durability and corrosion resistance.
• Complete Kit: Includes the ignition sensor, lead wires with connectors, and all necessary mounting hardware.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below.

Technical Specifications

Package Contents

• 1 x Ignition Sensor (Replaces 87-91019A2)
• 1 x Set of Lead Wires with Connectors
• 1 x Hardware Kit (mounting screws and fasteners)

Installation Guide

1. Safety First: Disconnect the boat's battery before beginning any electrical work.
2. Access the Distributor: Remove the distributor cap to locate the existing ignition sensor.
3. Disconnect Wires: Carefully unplug the wire connectors leading to the old sensor.
4. Remove Old Sensor: Unscrew the mounting hardware holding the sensor in place and remove it from the distributor.
5. Install New Sensor: Position the new ignition sensor and secure it using the fasteners from the provided hardware kit.
6. Connect New Wires: Attach the new lead wires and ensure the connectors are firmly seated.
7. Final Checks: Reinstall the distributor cap, reconnect the battery, and start the engine to test for proper operation.

Troubleshooting & FAQ

Q: How do I confirm this ignition sensor fits my MerCruiser engine?

A: This sensor is made for MerCruiser V6 and V8 engines (including 4.3L, 5.0L, 5.7L, 7.4L, and 8.2L models) from 1981-1997 that use a Thunderbolt IV or V ignition system. To ensure a perfect match, please check your engine model against the "Compatible Engine Models" table and verify your original part number with our cross-reference list.

Q: What are the common signs of a failing ignition sensor?

A: Symptoms of a faulty ignition sensor often include engine misfires, rough idling, difficulty starting, stalling, or a complete failure to start. You may also notice a significant loss of engine power during acceleration.

Q: Is this a complete kit for installation?

A: Yes, this kit includes the ignition sensor module, a set of lead wires with the correct connectors, and a hardware kit containing mounting screws and fasteners. It provides all the necessary components for a direct replacement.

Q: OEM vs. Aftermarket?

A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?

A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?

A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.