Alternator Conversion Kit – Fits MerCruiser 224/3.7L 470/485 Engines (Replaces 804916A1)

$815.49 $1,304.00

Shipping calculated at checkout.

Worry-free returns

You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.

Delivery and Shipping

Free standard shipping on all orders under 1 KG

If you have any questions, feel free to email us at info@sierramarines.com, and we’ll get back to you within 20–36 hours.

Product Details

This Alternator Conversion Kit upgrades the original stator charging system on MerCruiser 224/3.7L 4-cylinder 470/485 aluminum block engines (serial numbers 4625580 and up, 1978–1982) to a modern, reliable 68 Amp Delco-style alternator. It is designed specifically for stern drive applications and will not fit inboard models.

It serves as a direct replacement for Sierra part number 18-5953-1 and Mercury Marine/MerCruiser part number 804916A1.

Converts older stator charging systems to a high-output 68 Amp alternator.
Designed for stern drive installations only.
Requires a fuse kit (18-8220, sold separately) for engines equipped with a Delco starter.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
Sierra	18-5953-1
Mercury Marine	804916A1
MerCruiser	804916A1

Engine & Model Compatibility

Confirm your engine model and year in the table below.

This kit is engineered for specific MerCruiser aluminum block engines from the late 1970s and early 1980s that used a stator and water-cooled regulator.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
MerCruiser	470	190	4-Stroke	1978–1982	804916A1	Serial #4625580 and up, aluminum block only
MerCruiser	485	200	4-Stroke	1978–1982	804916A1	Serial #4625580 and up, aluminum block only
MerCruiser	224/3.7L	190-200	4-Stroke	1978–1982	804916A1	Serial #4625580 and up, aluminum block only

Technical Specs

Product Type: Alternator Conversion Kit
Installation: Stern Drive (will not fit inboard applications)
Alternator Output: 68 Amps
Alternator Style: Delco
Pulley Dimensions: 8.0" OD × 2.75" H (203.2 mm × 69.85 mm)
Required Clearance: Minimum 4" (101.6 mm) in front of engine for pulley installation
Product Dimensions: 29.0 cm L × 24.0 cm W × 24.0 cm H
Weight: 8.48 kg (18.7 lbs)
Engine Application: MerCruiser 470/485 aluminum block engines with serial number 4625580 and up
Original System: Converts stator charging system with water-cooled voltage regulator to alternator system
Additional Requirements: Fuse kit 18-8220 required for engines with Delco starter (sold separately)
Notes: Prestolite starters with remote solenoid do NOT require fuse kit
Warranty: Sierra limited lifetime warranty

What’s in the Box

1 × Delco Style 68 Amp Alternator
1 × Mounting Bracket (18-5968)
1 × Pulley (8.0" OD × 2.75" H)
1 × Belt (18-5949)
1 × Hardware Kit (mounting hardware)
1 × Wiring Kit
1 × Installation Instructions

Installation Notes

Disconnect the battery terminals to prevent electrical shorts.
Remove the old stator, flywheel, and water-cooled voltage regulator assembly.
Install the new pulley onto the crankshaft, ensuring there is a minimum of 4 inches of clearance.
Mount the new alternator bracket and alternator securely to the engine block.
Install the new drive belt and adjust for proper tension.
Connect the new wiring kit per the included instructions. A fuse kit (sold separately) is required if the engine uses a Delco starter.
Reconnect the battery terminals and start the engine to test the new charging system.

Troubleshooting & FAQ

Will this kit fit my inboard MerCruiser 470 engine?

No, this conversion kit is specifically designed for stern drive applications and will not fit inboard engine configurations.

How do I know if I have the original stator system?

Your engine likely has a stator system if it includes a flat, black, water-cooled voltage regulator, often mounted on the exhaust manifold. This kit is designed to replace that entire setup.

Do I absolutely need the separate fuse kit?

Yes, you must install the fuse kit (part #18-8220) if your engine is equipped with a Delco starter. If you have a Prestolite starter with a remote solenoid, the fuse kit is not required.

What is the benefit of converting to an alternator?

Alternators provide more consistent and higher amperage output, especially at idle, leading to better battery charging and more reliable electrical performance compared to the original stator system.

What are the signs my original stator is failing?

Common symptoms include a battery that won't stay charged, dimming lights at low RPM, or a voltmeter reading below 13 volts while the engine is running.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by the manufacturer's limited lifetime warranty against defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

Payment & Security

Payment methods

Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.