The CMT-393023Z is a zinc block anode designed for OMC, Johnson, and Evinrude outboard and sterndrive gearcases, providing essential protection against galvanic corrosion in saltwater environments.

This compact block-style anode mounts directly to the gearcase, protecting critical aluminum components by sacrificing itself during electrolysis. Zinc construction makes it the preferred choice for full saltwater use, ensuring reliable and consistent corrosion protection.

Key Features

OEM-style block anode design for OMC gearcases
Marine-grade zinc construction
Protects gearcase and internal components
Compact, direct-fit replacement
Ideal for saltwater applications
Proven, traditional corrosion protection

Engine Compatibility

Commonly used on:

OMC sterndrives and stringer drives
Johnson outboards: 50140 HP range
Evinrude outboards: 50200 HP range

Fits a wide range of classic OMC platforms
Also used on Cobra and similar gearcase designs

Serial Number Fitment Notice

Always confirm:

OEM reference: 393023 / 436745
Mounting location and bolt pattern
Gearcase compatibility

Correct fitment is critical for proper protection and installation.

When This Part Needs Replacement

Anode is 50% or more consumed
Uneven or rapid corrosion
Visible corrosion on gearcase
Routine maintenance or haul-out

Installation Notes

Mount to clean, bare metal surface
Ensure full contact with gearcase
Do not paint the anode
Tighten securely with proper hardware
Inspect regularly in saltwater use

Alternate / Cross-Reference Part Numbers

Camp Company: CMT-393023Z
Martyr: CM393023Z
OMC / BRP: 393023, 436745
Aluminum equivalent available for brackish water
Magnesium version available for freshwater

Parts Desk Insight

This is one of the most common small gearcase anodes on older OMC platforms. Because of its size, it tends to wear fasterso its a good idea to check it more frequently than larger hull anodes, especially on boats that stay in the water.