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Double Belt Alternator Pulley – Fits Volvo Penta AD31, AD41, AQAD30/40 Series (Replaces 841812)
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Double Belt Alternator Pulley – Fits Volvo Penta AD31, AD41 Series (Replaces 841812)
This aftermarket double belt alternator pulley is engineered for a precise fit on a wide range of Volvo Penta AD31, AD41, AQAD30, and AQAD40 series diesel engines, commonly found in applications from the late 1980s through the early 1990s.
This component is a direct replacement for Volvo Penta part number 841812, designed to restore original functionality and belt alignment for consistent alternator performance.
- Installation Method: Direct bolt-on replacement.
- Belt Compatibility: Designed for a double V-belt configuration.
- Warranty: Includes a 1-year warranty against manufacturing defects.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers.
| Brand | Part Number |
|---|---|
| Volvo Penta | 841812 |
Compatible Engine Models
Confirm your engine model/year in the table below.
| Brand | Model | Stroke | Years | OEM Part No. |
|---|---|---|---|---|
| Volvo Penta | AD31A, AD31B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AD31D, AD31L | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AD31P, AD31XD | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AQAD30A | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AQAD31A | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | KAD32P | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TMD31A, TMD31B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TMD31D, TMD31L-A | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TAMD31A, TAMD31B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TAMD31D, TAMD31P, TAMD31L, TAMD31S | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AD41A, AD41B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AD41D | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AD41L, AD41P | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AQAD40A, AQAD40B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | AQAD41A | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TAMD41A, TAMD41B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TAMD41D | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TAMD41H, TAMD41L, TAMD41M, TAMD41P | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TMD41A, TMD41B | 4-Stroke | Late 1980s–early 1990s | 841812 |
| Volvo Penta | TMD41D, TMD41L | 4-Stroke | Late 1980s–early 1990s | 841812 |
Technical Specifications
| Specification | Value |
|---|---|
| Product Type | Double Belt Alternator Pulley |
| Installation | Direct bolt-on replacement |
| Connection | Direct mount to alternator shaft |
| Fitting Type | Double V-belt |
| Warranty | 1-year warranty against manufacturing defects |
Package Contents
- 1 x Double Belt Alternator Pulley (841812)
Installation Guide
- Disconnect Power: Safely disconnect the vessel's battery terminals to prevent electrical hazards.
- Release Belt Tension: Loosen the alternator mounting bolts to release tension on the drive belts.
- Remove Belts: Carefully slide the old drive belts off the alternator pulley.
- Access the Pulley: If necessary, unbolt and remove the alternator from the engine for better access to the pulley retaining nut.
- Remove Old Pulley: Use an impact wrench or a pulley holder tool to secure the alternator shaft while unscrewing the central retaining nut. Remove the old pulley.
- Install New Pulley: Slide the new pulley onto the alternator shaft, ensuring it is properly seated against the spacer and shaft key.
- Secure Pulley: Reinstall and tighten the retaining nut to the manufacturer's recommended torque specification.
- Reinstall Alternator: Mount the alternator back onto the engine and reinstall the drive belts.
- Set Tension: Properly tension the belts according to your engine's service manual.
- Final Check: Reconnect the battery, start the engine, and check for proper pulley operation and belt alignment.
Troubleshooting & FAQ
How do I confirm this pulley fits my Volvo Penta engine?
First, check the compatibility table on this page to ensure your specific engine model (e.g., AD41B, TAMD31P) is listed. Second, verify that your current pulley is a double-belt type and corresponds to the OEM part number 841812. Visual comparison with our product photos is also recommended.
What are the signs that my alternator pulley needs replacing?
Common signs of a failing alternator pulley include a persistent squealing or grinding noise from the engine bay, visible wobbling or runout of the pulley while the engine is running, and cracked or worn-out grooves where the V-belts sit.
Are any special tools required for installation?
You will need standard mechanic's tools, a socket set, and a wrench. To remove the old pulley's central nut, an impact wrench is highly effective. Alternatively, you may need a specific pulley holding tool to prevent the alternator shaft from spinning while you loosen the nut with a breaker bar.
OEM vs. Aftermarket?
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.
How fast do you ship and how much does it cost?
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.
What is your warranty and return policy?
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.
We can ship to virtually any address in the world with free shipping available for most regions.
For our typical US and Canadian customers , our shipping timeframes are as follows:
- Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
- US warehouse shipment: orders will be delivered within 5 days after placing the order.
- China warehouse shipment: orders will be delivered about 12 days after placing the order.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.
As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.
We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.
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