Sierra 18-99525 Lower Unit Adapter Kit, Cross-Reference 551-33-1, 551-34PV, 551-34HA, 551-34HB

The Sierra 18-99525 Lower Unit Adapter Kit is a specialty tool kit built for connecting lower unit wiring and sending components on outboard and sterndrive applications where the factory connector needs to be adapted. The kit bundles a set of individual adapter pieces so that installers have the correct connector on hand for the job rather than sourcing each piece separately. It is designed as a direct, drop-in wiring solution for technicians and boat owners performing lower unit service, trim sender replacement, or related wiring repairs. The kit ships complete with the pieces listed below, letting you match the correct adapter to your application without piecing together individual components from multiple sources. Because lower unit wiring adapters vary by connector style and pin configuration, the Sierra 18-99525 is cross-referenced to several equivalent part numbers to help buyers confirm they are ordering the correct kit for their existing wiring harness. As with any lower unit wiring component, check your existing connector style and the manufacturer's recommended part number for your specific application before installing to ensure a proper fit.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-99525
• Product Name: Adapter Kit
• Category: Specialty Tools
• Weight: 0.4 pounds
• UPC: 808282394882
• Kit Contents: 551-334M, 551-334S, 551-334V, 551-33TN, 551-33UN
• Compatible Part Numbers: 551-33-1, 551-34PV, 551-34HA, 551-34HB

Replaces (OEM)

• 551-33-1
• 551-34PV
• 551-34HA
• 551-34HB

Frequently Asked Questions

What is included in the Sierra 18-99525 Lower Unit Adapter Kit? The kit includes five individual adapter pieces: 551-334M, 551-334S, 551-334V, 551-33TN, and 551-33UN, packaged together as the Sierra 18-99525 Adapter Kit.

What part numbers is the Sierra 18-99525 compatible with? The Sierra 18-99525 is compatible with part numbers 551-33-1, 551-34PV, 551-34HA, and 551-34HB, so it can be cross-checked against any of those numbers when confirming fitment.

How much does the Sierra 18-99525 Adapter Kit weigh? The Sierra 18-99525 Lower Unit Adapter Kit weighs 0.4 pounds.

Is this a genuine Sierra part? Yes, 18-99525 is the Sierra manufacturer part number for this Lower Unit Adapter Kit.

What is the Sierra 18-99525 used for? It is a lower unit adapter kit used to connect wiring components, such as lower unit or trim sender connections, where an adapter is needed to mate to the existing harness.

Does the Sierra 18-99525 fit my boat's lower unit wiring? Fitment depends on your connector style, so check your existing part number against the compatible numbers 551-33-1, 551-34PV, 551-34HA, and 551-34HB before ordering the Sierra 18-99525.

How many adapter pieces come in the kit? The Sierra 18-99525 kit contains five adapter pieces: 551-334M, 551-334S, 551-334V, 551-33TN, and 551-33UN.

What category of product is the Sierra 18-99525? The Sierra 18-99525 is classified as a specialty tool, specifically a lower unit adapter kit.

Can I order individual adapters instead of the full kit? The Sierra 18-99525 is sold as a complete kit containing all five adapter pieces (551-334M, 551-334S, 551-334V, 551-33TN, 551-33UN) rather than as individual components.

How do I confirm I am ordering the correct adapter kit? Compare your existing lower unit wiring connector's part number to the Sierra 18-99525's compatible numbers (551-33-1, 551-34PV, 551-34HA, 551-34HB) to confirm a proper match before installing.