Sierra 18-3151 Water Coupling Assembly, OEM 47-43026T11, for Alpha One Gen II Drives

The Sierra 18-3151 Water Coupling Assembly connects the water pump housing to the drive unit, directing raw cooling water into the engine's cooling circuit. It is a direct-fit replacement coupling designed for Alpha One Gen II drives and multiple outboard applications, and it cross-references to OEM number 47-43026T11.

The coupling is finished in white with a machined exterior for a precise, consistent fit against the mating water pump housing. It ships as a single-piece assembly (one coupling per package) so installers can replace a worn or leaking coupling without sourcing a full water pump kit. Because raw water passes directly through this component, a cracked or degraded coupling is a common cause of overheating or reduced water flow, making the 18-3151 a straightforward preventive-maintenance or repair item during a water pump service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-3151
• Color: White
• Item Dimensions: 7.25 x 6 x 1.5 inches
• Connector Type: Coupling
• Exterior Finish: Machined
• Thread Type: NPT
• Number of Pieces: 1
• Weight: 0.06 pounds
• UPC: 808282112875
• OEM Cross Reference: 47-43026T11
• Compatibility: Alpha One Gen II drives and multiple outboard applications

Fitment

Fits Alpha One Gen II drives and multiple outboard applications.

Replaces (OEM)

• 47-43026T11

Frequently Asked Questions

What does the Sierra 18-3151 Water Coupling Assembly fit? The 18-3151 is designed for Alpha One Gen II drives and multiple outboard applications where a water coupling connects the water pump housing to the drive unit.

Is the 18-3151 coupling equivalent to OEM part 47-43026T11? Yes, Sierra 18-3151 cross-references directly to OEM number 47-43026T11, so it is a direct equivalent for that coupling.

What color is this water coupling assembly? It is white with a machined exterior finish, part number 18-3151.

What are the dimensions of the 18-3151 coupling? The Sierra 18-3151 measures 7.25 x 6 x 1.5 inches as a complete assembly.

How much does the 18-3151 Water Coupling Assembly weigh? It weighs 0.06 pounds, making it a lightweight single-piece component.

How many pieces come in the package? One coupling assembly ships per package; the 18-3151 is sold as a single unit, not a kit.

Why would I need to replace this water coupling? A cracked, worn, or leaking coupling like the 18-3151 can restrict raw water flow to the engine, so replacing it is a common step when diagnosing or preventing engine overheating.

Does the 18-3151 include a thread type? Yes, the coupling uses NPT (National Pipe Thread) threading.

Is this a genuine Sierra part or an aftermarket copy? The 18-3151 Water Coupling Assembly is a genuine Sierra-branded part manufactured under Sierra's own part number and packaging.

Can I use this coupling with a full water pump kit installation? Yes, the 18-3151 coupling can be installed alongside a water pump housing and impeller as part of a broader water pump service, or replaced on its own if only the coupling has failed.

What is the UPC for the Sierra 18-3151? The UPC for this water coupling assembly is 808282112875.