# 99502A13 Mercruiser Regulator | Genuine Used Part

🔧 Product Description

  

Genuine MerCruiser Water-Cooled Voltage Regulator - Part Number: 99502A13

  

A genuine Mercury MerCruiser water-cooled voltage regulator for 3.7L / 224 CID inline 4-cylinder sterndrive engines. This 40 amp regulator is used in the MerCruiser 470, 485, 488, 165, 170, 180, 190 and 3.7L charging-system family.

  

⚙️ Key Features

  

• Genuine Mercury MerCruiser voltage regulator

• Correct Mercury part number 99502A13

• Supersedes earlier 99502A9 regulator assembly

• Water-cooled 40 amp regulator for MerCruiser 3.7L / 224 CID 4-cylinder engines

• Used on sterndrive charging systems with the water-cooled regulator / rectifier configuration

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 99502A13 current Mercury / MerCruiser service reference

• 99502A12 earlier related regulator reference

• 99502A9 → Superseded by 99502A13

• 99502A8 / 99502A7 / 99502A4 earlier related 3.7L regulator references

  

OEM / Related Numbers:

  

• 99502A13

• 99502A12

• 99502A9

• 99502A8

• 99502A7

• 99502A4

• 99502

• 77305A2

• 86255A2

• 86255A3

• Related regulator / rectifier conversion reference

  

Aftermarket / Verified Equivalents:

  

• CDI Electronics: 194-9502

• Sierra: 18-99421

• CDI Electronics: 194-9502-4

• Aftermarket water-cooled regulator family: 99502A7 / 99502A9 / 99502A13

  

🚤 Compatibility

  

Commonly used on:

  

• MerCruiser 3.7L / 224 CID inline 4-cylinder sterndrive charging systems using the water-cooled regulator

  

Typically suits:

  

• Engine models:

• MerCruiser 470 2BBL 4-cylinder sterndrive, 1976-1984

• MerCruiser 485 2BBL 4-cylinder sterndrive, 1980-1984

• MerCruiser 488 2BBL 4-cylinder sterndrive, 1980-1984

• MerCruiser 170 4-cylinder sterndrive, 1985-1986

• MerCruiser 190 4-cylinder sterndrive, 1985-1986

• MerCruiser 165 4-cylinder sterndrive, 1987

• MerCruiser 180 4-cylinder sterndrive, 1987

• MerCruiser 3.7L 4-cylinder sterndrive, 1988-1989

• MerCruiser 3.7LX 4-cylinder sterndrive, 1988-1989

  

• HP Range: approximately 165HP - 190HP in listed MerCruiser 3.7L applications

• Engine Type: MerCruiser 3.7L / 224 CID inline 4-cylinder petrol sterndrive

• Year Range: 1976 - 1989

• Charging System: 40 amp water-cooled regulator / rectifier configuration

  

🔌 Function

  

The voltage regulator rectifies and regulates alternator / stator charging output so the battery and electrical system receive controlled charging voltage while the engine is running.

  

Common signs of failure:

  

• Battery not charging

• Charging voltage too high or unstable

• Gauge voltage spikes at higher RPM

• Repeated battery boiling or electrical component damage

• No output after stator and wiring checks

• Water leak, corrosion or blockage at the regulator cooling connection

• Burn marks, heat damage or melted wiring at regulator terminals

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 300.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Electronic Components | ECU CDI & Electrical Parts

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 300.00 AUD | In stock |

## Images

- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part
- 99502A13 Mercruiser Regulator | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/99502a13-mercruiser-regulator-genuine-used-part)
> Updated: 2026-06-29