21257633 Pulley | Genuine Volvo Penta Part

🔧 Product Description

Genuine pulley used in the inlet and exhaust-system supercharger drive of Volvo Penta D11 marine engines.

🚤 Compatibility

Typically suits:

• Volvo Penta D11B4-A MP
• Volvo Penta D11B2-A MP
• Volvo Penta D11A-C MP
• Volvo Penta D11A-D MP

• Engine Family: D

⚙️ Key Features

• Genuine Volvo Penta supercharger pulley
• Correct belt-groove geometry
• Maintains designed supercharger speed
• Replaces earlier pulley 21148809
• Used with dedicated adapter ring and mounting screws

🔌 Function

The pulley transfers belt drive to the supercharger at the speed required to provide boosted intake airflow.

⚠️ Common Signs of Failure

• Belt misalignment
• Cracked belt grooves
• Bearing or hub movement
• Reduced boost or supercharger speed

🛠️ Service Notes

• Inspect the belt running surfaces before fitting — a pulley with glazed, scored, pitted or rust-roughened grooves will chew through a new belt in very little running time
• Check that the pulley runs true and that its bearing or bush turns smoothly with no roughness or side play; fit a new belt whenever a pulley is changed
• Confirm that every pulley in the drive lies in the same plane and that the belt profile matches each groove — misalignment shows up as belt dust, squeal or a worn belt edge and will destroy a new belt quickly
• Fit onto a clean, dry, burr-free shaft or hub face and tighten the retaining fasteners in the sequence and to the figures given in the workshop manual for your engine
• Turn the engine over by hand before starting to confirm the belt is fully seated in every groove and that nothing fouls, then recheck belt tension after the first running period

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21257633 → Supersedes 21148809

OEM / Related Numbers

• 21148809 earlier number superseded by this part

📦 Condition

• Genuine Volvo Penta part
• Brand new
• Supplied in original or equivalent packaging