PDOK Alternator for Mercury Outboard 135–150HP — 12V 55A, CW Rotation, S4 Pulley (64mm)

PDOK Alternator 21453 is a direct-fit 12V, 55A replacement alternator built to match Mercury outboard OEM specs for reliable charging and straightforward installation.

This alternator is designed as a compatible replacement for specific Mercury Marine 135–150HP four-stroke outboards. It reproduces the original alternator’s mounting points, electrical terminals and pulley size so you can restore charging performance without modifying wiring or brackets. Built from quality components and bench-tested, the unit supports common engine models with several OEM cross-reference numbers.

Which Mercury outboards will this PDOK alternator fit?

The alternator fits a range of Mercury four-stroke models and model years listed by serial number and designation. It covers 135HP and many 150HP variants including Pro XS, SeaPro and XL configurations across the indicated serial ranges and years.

• Compatible with Mercury 135.0HP (SN 2B131942 & up)
• Compatible with 150.0HP, 150 Pro XS, 150 SeaPro, 150XL, 150L across specified SN ranges and years
• Cross-references OEM: 8M0057693, 8M0062515, 8M0065239, AND0626, 400-52434

What are the electrical and mechanical specifications?

This unit delivers 12 volts and 55 amps with clockwise rotation and uses a four-groove S4 pulley sized 64mm OD. Terminal types and mounting details match the original alternator so electrical connections and bolt patterns align with factory setup.

• Voltage: 12V, Amperage: 55A, Rotation: CW
• Pulley class: S4 groove, pulley diameter: 64mm OD
• Terminals: B+ M6x1.00, S spade, L spade
• Mounting ears: mixed threaded and unthreaded holes as specified for direct fit

How reliable is the PDOK replacement and what warranty/support is included?

PDOK alternators are assembled from premium components and individually tested to ensure functional equivalence with the original equipment. The part comes with a return period and a one-year warranty to cover manufacturing defects, plus seller support for troubleshooting and fitment questions.

• 30-day free return window
• 365-day warranty against manufacturing defects
• Pre-shipment quality testing for installation readiness

How straightforward is installation and what should I check before buying?

Because this alternator reproduces the OEM form and function, installation is typically direct — no special adapters or wiring changes should be necessary. Before ordering, confirm your engine’s model, horsepower, and serial number match the listed applications and verify belt alignment with the S4 pulley size.

• Verify engine model, HP and serial number against the application list
• Confirm belt width and routing match S4 four-groove pulley
• Inspect mounting bolt sizes and terminal access for compatibility

Who is this for: This PDOK Alternator 21453 is aimed at boat owners, marine mechanics and fleet managers who need a direct-replacement charging unit for Mercury 135–150HP four-stroke outboards. Choose this part if you want an alternator matched to OEM mounting and terminal specs, backed by quality testing and a one-year warranty, without altering the engine’s original electrical or belt systems.