---
product_id: 288921023
title: "Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511"
brand: "aa ignition"
price: "A$89"
currency: AUD
in_stock: true
reviews_count: 5
url: https://www.desertcart.com.au/products/288921023-replacement-inboard-ignition-coil-compatible-with-mercruiser-thunderbolt-iv-v
store_origin: AU
region: Australia
---

# Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511

**Brand:** aa ignition
**Price:** A$89
**Availability:** ✅ In Stock

## Quick Answers

- **What is this?** Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 by aa ignition
- **How much does it cost?** A$89 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.com.au](https://www.desertcart.com.au/products/288921023-replacement-inboard-ignition-coil-compatible-with-mercruiser-thunderbolt-iv-v)

## Best For

- aa ignition enthusiasts

## Why This Product

- Trusted aa ignition brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Description

Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511

## Features

- REPLACEMENT INBOARD MARINE ENGINE IGNITION COIL - The ignition coils or ignition coil plug provides spark for your engine. Over time the factory ignition coil packs can fail leading to hard starting or losing power when the engine is hot or your boat may run erratically. Replace your faulty ignition coil and restore performance and driveability on your boat.     FITS V6, V8 308 & 350 ENGINES WITH THUNDERBOLT IV & V IGNITION SYSTEM - Only works with HEI (High Energy Ignition) Systems and will not work with Point Ignition Systems. This replacement ignition coil by AA Ignition made by an original equipment supplier will get your 4.3L, 5.0L, 5.7L, 6.2L, 7.4L & 8.2L Mercruiser GM petrol engines with Thunderbolt 4 and 5 ignition systems.     REPLACES PART# Sierra 18-5438, Mercury 392-805570A2, 392-7803A4, 392-805570A1, GLM 72115, PerTronix 40511, Mallory 9-29701, Pro Marine 64570, RL5438. The ignition coil of your boat can easily be located beside the distributor which is found in the engine.     OEM FIT, QUALITY, FINISH - While this is not a genuine MerCruiser, Sierra, PerTronix, Mercury, GLM or OMC part, it is a direct replacement for your OMC Cobra Sterndrive boat or MerCruiser boat engine and it will appear, fit and work like the factory part. Save time and hundreds of dollars off of dealer prices by replacing the part yourself.     2 YEAR OR 24,000 MILE WARRANTY - This ignition coil pack comes complete with a 2 year or 24, 000 mile warranty. If the coil ever fails on your boat within the warranty period, simply contact us for a replacement. Save time and money by taking advantage of this warranty.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Brand | AA Ignition |
| Vehicle Service Type | Boat |
| Item Weight | 0.6 Kilograms |
| Connector Gender | Male-to-Female |
| Installation Type | Plug In |
| Manufacturer | AA Ignition |
| Automotive Fit Type | Vehicle Specific Fit |
| OEM Part Number | 18-5438, 3000-8M0079202, 392-7803, 64570, RL5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511, 9-29701 |
| Item Weight | 1.32 pounds |
| Package Dimensions | 7.2 x 3.58 x 3.31 inches |
| Is Discontinued By Manufacturer | No |
| Manufacturer Part Number | 18-5438 |

## Product Details

- **Brand:** AA Ignition
- **Vehicle Service Type:** Boat
- **Item Weight:** 0.6 Kilograms
- **Connector Gender:** Male-to-Female
- **Installation Type:** Plug In

## Images

![Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 - Image 1](https://m.media-amazon.com/images/I/61R3DWNZO7L.jpg)
![Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 - Image 2](https://m.media-amazon.com/images/I/81BMDxPMbzL.jpg)
![Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 - Image 3](https://m.media-amazon.com/images/I/81zRz9rimwL.jpg)
![Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 - Image 4](https://m.media-amazon.com/images/I/81dpTRiIeFL.jpg)
![Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511 - Image 5](https://m.media-amazon.com/images/I/81rsc54NqtL.jpg)

## Customer Reviews

### ⭐⭐⭐ 







  
  
    Doesn't include boot or spade terminals shown
  

*by G***. on Reviewed in Canada on 13 March 2020*

Does not come with the rubber boot or the spade terminals shown. Otherwise looks fine. Not installed yet so can't comment on performance.

### ⭐⭐⭐⭐⭐ 







  
  
    Good quality works great
  

*by C***  on Reviewed in Canada on 4 October 2020*

Works great for 2005 mercruiser 4.3 with thunderbolt v ignition

### ⭐⭐⭐⭐⭐ 







  
  
    AS advertized
  

*by R***D on Reviewed in Canada on 5 November 2021*

Looks ok

## Frequently Bought Together

- Replacement Inboard Ignition Coil - Compatible with MerCruiser Thunderbolt IV and V Ignition Systems with HEI - Replaces 18-5438, 392-805570A2, 392-7803A4, 392-805570A1, 72115, 40511
- THUNDERBOLT Distributor Cap and trigger wheel Rotor Kit with gasket and screws for Mercruiser 5.0, 5.7, 7.4, 8.2 5.0L 5.7L 7.4L 8.2L V8 engines 805759Q3, 805759T3 18-5935.
- B. Ignition Sensor Kit for MerCruiser Thunderbolt I IV Distributor

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**Shop now:** [https://www.desertcart.com.au/products/288921023-replacement-inboard-ignition-coil-compatible-with-mercruiser-thunderbolt-iv-v](https://www.desertcart.com.au/products/288921023-replacement-inboard-ignition-coil-compatible-with-mercruiser-thunderbolt-iv-v)

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*Product available on Desertcart Australia*
*Store origin: AU*
*Last updated: 2026-02-19*