Sierra 18-7688 Fuel Injector for Mercruiser 6.2L 377 V-8 MPI Engines

The Sierra 18-7688 is a fuel injector engineered for Mercruiser 6.2L 377 V-8 engines equipped with multi-port fuel injection (MPI). It is built to deliver precise fuel metering into the engine's intake, supporting the combustion timing and fuel efficiency these V-8 marine engines depend on. This injector is application-specific to the 6.2L 377 V-8 platform, covering the standard MPI configuration as well as the MPI Horizon and MPI Horizon MIE variants, including versions equipped with DTS (Digital Throttle and Shift) electronic controls.

Coverage spans model years 2002-2004 and 2004-2007 for the standard MPI, MPI Horizon, and MPI Horizon MIE configurations, and 2005-2007 for the DTS-equipped versions of those same engine families. Because fitment is tied to specific engine serial number ranges within these years, confirming your engine's serial number against the exact range is recommended before ordering. The injector is compact, measuring 0.39 x 0.39 x 0.39 inches, and weighs 0.06 pounds, consistent with the small form factor required to mount directly on the intake manifold alongside its companion injectors.

As a direct-fit replacement part, the 18-7688 is intended for engine owners performing fuel system maintenance, diagnosing a misfiring or rough-running cylinder, or replacing a failed or clogged injector as part of a full-set service.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7688
• Product Type: Fuel Injector
• Engine Application: 6.2L 377 V-8 (Mercruiser MPI, MPI Horizon, MPI Horizon MIE, and DTS variants)
• Model Years: 2002-2004 and 2004-2007 (MPI, MPI Horizon, MPI Horizon MIE); 2005-2007 (DTS variants)
• Weight: 0.06 pounds
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• UPC: 808282287399

Fitment

• Mercruiser 6.2L 377 V-8 MPI, model years 2002-2004 and 2004-2007
• Mercruiser 6.2L 377 V-8 MPI Horizon, model years 2002-2004 and 2004-2007
• Mercruiser 6.2L 377 V-8 MPI Horizon MIE, model years 2002-2004 and 2004-2007
• Mercruiser 6.2L 377 V-8 MPI DTS, MPI Horizon DTS, and MPI Horizon MIE DTS, model years 2005-2007

Frequently Asked Questions

What engine does the Sierra 18-7688 fuel injector fit? The 18-7688 is built for Mercruiser 6.2L 377 V-8 engines running multi-port fuel injection (MPI), including the standard MPI, MPI Horizon, and MPI Horizon MIE configurations.

Does the 18-7688 work with DTS-equipped engines? Yes, this injector also fits the DTS (Digital Throttle and Shift) versions of the MPI, MPI Horizon, and MPI Horizon MIE 6.2L 377 V-8 engines, covering model years 2005-2007.

What model years does part number 18-7688 cover? Coverage is 2002-2004 and 2004-2007 for the standard MPI, MPI Horizon, and MPI Horizon MIE engines, and 2005-2007 for the DTS variants of those same engine families.

How much does the Sierra 18-7688 fuel injector weigh? It weighs 0.06 pounds, in line with the compact size of a single-cylinder marine fuel injector.

What are the dimensions of this fuel injector? The Sierra 18-7688 measures 0.39 x 0.39 x 0.39 inches.

Is the 18-7688 an OEM or aftermarket part? It is sold under the Sierra brand as part number 18-7688, engineered specifically for the Mercruiser 6.2L 377 V-8 MPI engine family listed in its application coverage.

Will one 18-7688 injector service a full engine rebuild? This listing is for a single fuel injector, part number 18-7688; a V-8 engine uses multiple injectors, so quantity needed depends on how many cylinders require replacement.

How do I know if my Mercruiser 6.2L engine uses the 18-7688? Fitment for the 18-7688 depends on your engine's specific serial number range within the 6.2L 377 V-8 MPI, MPI Horizon, MPI Horizon MIE, or DTS families, so confirming your engine's serial number against those ranges is the reliable way to verify fit.

What symptoms indicate a fuel injector like the 18-7688 needs replacing? A clogged or failed injector on a 6.2L 377 V-8 typically shows up as a rough-running or misfiring cylinder, reduced power, or uneven idle, which the 18-7688 is designed to correct when replaced.

Does the 18-7688 fit non-MPI 6.2L 377 V-8 engines? No, this part is specific to fuel-injected (MPI) versions of the 6.2L 377 V-8, including its Horizon, Horizon MIE, and DTS variants.