Description

Mercury 88517 is a genuine OEM reducing fitting used in selected Mercury MerCruiser fuel and engine-system applications. Dealer listings identify it as 22-88517 FITTING Reducing, and Mercury parts diagrams also show it as a current service part in applicable assemblies.

Key Features
Genuine Mercury Marine / Quicksilver OEM part number 88517. Commonly listed as a reducing fitting, with Mercury shorthand format 22-88517 in dealer catalogs. It is also identified in a current Mercury fuel module service kit as a 3/8-inch hex adapter, which helps clarify its role as a connection fitting rather than a hose or plug.

Engine Compatibility
This fitting appears in a broad range of Mercury MerCruiser applications, including older MerCruiser gas-engine packages and later high-performance models. One dealer “Where Used” listing shows fitment across applications such as 300 Tempest, TRS packages, and Mercury Racing 1025 SCi, 1075 SCi, and 1200 SCi serial ranges, while current parts diagrams also show it inside a fuel module component breakdown. Exact fitment should still be confirmed by model and serial number before ordering.

Serial Number Fitment Notice
Please confirm compatibility by your exact Mercury MerCruiser engine or drive serial number in the Mercury parts catalog before purchase. This is especially important with fittings, since similar-looking connectors can differ by thread size, reduction, and assembly location.

When This Part Needs Replacement
This fitting is typically replaced when the original connector is damaged, corroded, leaking, stripped, or being renewed during fuel-module or related service work. That service context is supported by the part appearing in a Mercury fuel module kit and in current module component diagrams.

Installation Notes
Install only the exact fitting specified for the assembly being serviced. Because Mercury identifies this part as a reducing fitting and also uses it as a hex adapter in a fuel module kit, thread match and sealing integrity matter during installation. Follow the correct Mercury service-manual procedure for the specific application.

Alternate / Superseded Part Numbers

• 22-88517
  No confirmed superseded number was established from the sources reviewed.

Parts Desk Insight
Small fittings like this often get overlooked during repairs, but they are critical to keeping the system sealed and routed correctly. Matching the exact Mercury part number is the safest way to avoid thread mismatch or connection issues during reassembly. This is a practical service inference supported by Mercury’s use of the part as a reducing/adapter fitting in assembled systems.

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