Volvo Penta DuoProp Rear Propeller Nut | OEM Part 21631162

Volvo Penta DuoProp Rear Propeller Nut — OEM Part 21631162

Genuine Volvo Penta OEM rear propeller nut for selected DuoProp and DPS drive applications. This is the correct fastening hardware for the rear propeller position on compatible Volvo Penta DuoProp drives, used to secure the propeller assembly to the drive shaft. Current parts references also show 3851341 as the superseded earlier part number.

Part Information

• Part Number: 21631162
• Brand: Volvo Penta
• Official Product Type: Rear Propeller Nut — DuoProp / DPS
• System: Propulsion — DuoProp Drive Hardware
• Weight: Approx. 0.071 kg
• Socket Size: 1 3/16 in. deep socket (confirmed for at least one listed application)

Supersession & Cross-Reference

• Current OEM Part Number: 21631162
• Supersedes: 3851341
• Always confirm the current part number against your drive’s parts diagram before ordering

Compatible Applications

• Volvo Penta DPS (DuoProp) drive applications — rear propeller position
• Selected Volvo Penta D, F, and I series DuoProp rear propeller hardware configurations
• F-series rear propeller nut applications as listed in Volvo Penta hardware diagrams
• Always confirm fitment by drive model, propeller series, and serial number before ordering — DuoProp hardware specifications vary by drive generation and propeller series

Serial Number & Fitment Notice

Fitment must be confirmed by drive model, propeller series, and serial number before ordering. Volvo Penta DuoProp hardware can vary by drive generation and propeller series. Use your drive’s parts diagram to verify the correct nut for your specific rear propeller configuration.

When to Replace

Replace this propeller nut when:

• The nut is rounded, damaged, or shows tool marks from previous removal
• Thread condition is compromised or corrosion is present
• The nut no longer secures the propeller correctly
• The propeller hardware stack is being refreshed during seasonal or annual service
• Propeller removal reveals worn or seized fastening hardware

Installation Notes

• Confirm the exact drive model and propeller series before ordering
• Use a 1 3/16 in. deep socket where applicable — verify the correct tool for your specific drive
• Inspect shaft threads and related thrust washer or spacer hardware during service
• Do not reuse badly corroded or damaged hardware — replace during propeller service
• Torque to the specification in the Volvo Penta service manual for your drive

Technical FAQ

What is the difference between 21631162 and the superseded 3851341?
3851341 is the earlier part number that 21631162 supersedes. The current OEM replacement is 21631162. If your parts diagram or previous order shows 3851341, order 21631162 as the current equivalent.

Is this the front or rear propeller nut?
This is the rear propeller nut for DuoProp applications. DuoProp drives use separate front and rear propeller nuts — confirm which position you need before ordering.

What socket size do I need?
Current references for this part note a 1 3/16 in. deep socket for at least one application. Verify the correct tool specification for your specific drive in the Volvo Penta service manual.

Parts Desk Insights

Best Use Case: This is the correct OEM replacement for DuoProp drive owners refreshing rear propeller hardware during seasonal service, propeller changes, or after discovering corrosion or thread damage on the existing nut. It is a low-cost part that is worth replacing any time the propeller is removed rather than reusing hardware that shows wear.

Common Customer Issue: The most frequent issue is customers ordering without confirming whether they need the front or rear propeller nut — DuoProp drives use different nuts for each position. Also confirm the drive series and propeller series against the parts diagram, as DuoProp hardware varies across D, F, and I series configurations. When in doubt, cross-reference by the superseded number 3851341 or your drive’s parts diagram.