The Mercury Fuel Injector OEM Part Number 98818 and 988181 are the BOSCH OEM injectors used on legendary Mercury Racing 2.0 Liter F1, 2.4 Liter, and 2.5 Liter EFI engines—including the Bridgeport, 260 EFI, 280 ROS, 300 Drag, and S3000.
 
On these engines, the injector sits in the fuel rail and seals into the side of the block with dedicated grommets and seals. The ECU-controlled injector receives regulated high-pressure fuel and meters it into each cylinder’s intake path at a rate matched to engine load and RPM.
 
How the Mercury 98818 Injector Works in the EFI System
On Mercury Racing 2.0, 2.4, and 2.5L EFI engines, OEM part number 98818 is installed in the fuel rail and sealed into the side-injected block with specific grommets and O-rings. The ECU pulses each injector open and closed in milliseconds, controlling how much fuel enters each cylinder’s intake port.
 
Because these engines are typically run hard and spun high, precise metering is essential. Correct injector flow and spray pattern support clean idle, sharp throttle response, strong mid-range, and safe air/fuel ratios at wide-open throttle. A properly matched set of injectors lets the engine run smoother, make better power, and stay safer at the limit.
 
Common Symptoms of a Failing Mercury 98818 Injector
As the original Bosch 98818 injectors age, they can accumulate varnish, dirt, or internal wear. In practice, issues with one or more injectors may show-up as rough idle, a single-cylinder misfire under load, hesitation when you roll into the throttle, or a noticeable loss in top-end RPM and speed.
 
A stuck-open injector can flood its cylinder, causing a strong fuel smell and wet plugs. A restricted or partially clogged injector more often causes lean behavior: hotter cylinder readings, rough running at higher RPM, or plug readings that don’t match the others. On serious race boats, small flow differences are often visible in plug chops or EGT data long before casual symptoms appear.
 
In many cases, a proper clean and flow test can bring original Mercury injectors back into spec, as long as the coil and internal components are still healthy. Severely corroded or physically damaged injectors should be replaced with the current OEM number.
 
Mercury OEM Part Number 98818 and Supersessions
The original Mercury / Bosch injector—98818 / 988181 / 8M0192275—is designed around the ECU calibration for these engines, including flow curve and spray pattern. Generic replacements with different characteristics can change mixture distribution and reduce tuning margin.
 
OEM-spec injectors also match the physical dimensions, tip length, and body shape required by the side-injected block and fuel rail hardware. That ensures proper seating and sealing with the correct grommets and seals, exactly as shown in Mercury and racing documentation.
 
Seals, Grommets, and Hardware Associated with 98818
The injector is only one part of the EFI package. The upper and lower grommets and seals used on Mercury’s side-injected EFI outboards—commonly referenced as 25-99123 and 26-94219—are designed specifically to work with the injector style identified as 24-98818.
 
These components seal the injector to the block and prevent fuel leaks and unmetered air from entering the intake path. Parts diagrams also show hold-down brackets (98716), spacers (98717), and related hardware that clamp the injectors into the rail and maintain proper seating pressure.
 
Whenever injectors are serviced or replaced, renewing the grommets, seals, and related EFI hardware is strongly recommended. Fresh soft parts help guarantee a tight, leak-free installation and preserve EFI integrity—especially important on high-performance and racing engines.
 
Buckshot Racing #77 Clean & Flow Service and EFI Parts
To support Mercury Racing owners, Buckshot Racing #77 offers a full professional clean-and-flow service for Mercury race injectors, including those originally supplied as OEM part number 98818.
 
Your used injectors are ultrasonically cleaned, filtered, and bench-tested for flow, spray pattern, and coil performance, then matched as closely as possible to bring your set back to factory-level flow specs. We use only the top-of-the-line flow bench, cleaning fluids, and replacement parts. 
 
On this website, Buckshot Racing #77 also supplies key EFI service parts to support that work—injector filter screens, Mercury EFI hose, and the correct upper and lower grommets and seals—so you can refresh the entire injector system at the same time.
 
With cleaned and flow-matched injectors plus fresh EFI hardware, your 2.0 Liter Champ, 240 Bridgport, 260 EFI, 280 ROS, 300 Drag, or S3000 is far better prepared to run hard, consistently, and safely.
 
For technical inquiries or customization options, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com