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HEI Ignition Coil for MerCruiser Thunderbolt IV V 392-7803A4 392-805570A2
$76.99
Sale price
$76.99
Regular price
Available to Order
This HEI Ignition Coil is a high-energy ignition component compatible with MerCruiser Thunderbolt IV and V marine engines and matches OEM Part# 392-7803A4 and 392-805570A2.
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I needed a forklift part and wasn’t sure which one fit. They asked for the model and serial number, got back to me quickly, and made sure I ordered the right one. Really helpful.
Randy W. — Verified customer
Product Overview
This HEI Ignition Coil is a high-energy ignition component compatible with MerCruiser Thunderbolt IV and V marine engines and matches OEM Part# 392-7803A4 and 392-805570A2.
Product Overview
Key Features & Performance
- High Energy Ignition (HEI) design delivers a powerful spark for improved combustion
- Direct replacement for MerCruiser Thunderbolt IV and V ignition systems
- Epoxy-filled construction resists vibration and moisture common in marine environments
- Includes mounting bracket and hardware for straightforward installation
- Meets or exceeds OEM specifications for reliable engine starts and smooth idle
Fitment & Compatibility
- MerCruiser Thunderbolt IV ignition systems
- MerCruiser Thunderbolt V ignition systems
- Replaces OEM part numbers 392-7803A4 and 392-805570A2
Common Uses
- Replacing faulty or worn ignition coils on inboard and sterndrive MerCruiser engines
- Restoring spark performance on Thunderbolt IV and V equipped marine powerplants
- Upgrading from conventional coils to a high-energy design for better reliability
Technical Specifications
- Part Number(s): 392-7803A4, 392-805570A2
- Type: HEI Ignition Coil
- Primary Resistance: 0.5���1.5 ohms
- Secondary Resistance: 8���12 k ohms
Frequently Asked Questions
Q: Will this coil work on a standard MerCruiser distributor? A: Yes, it is designed for Thunderbolt IV and V distributors but may fit other models if the mounting pattern and electrical specs match.
Q: Do I need to replace the spark plug wires at the same time? A: It is recommended to inspect your wires; HEI coils produce higher voltage and worn wires may cause misfire.
Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number. Verify fitment before purchase.