The Mercury Racing Short Trim Ram Seal Repair Kit, OEM part number 8M0244476, is the genuine Mercury service kit used to rebuild the single-ram hydraulic trim cylinders found on many Mercury Racing and Mercury High-Performance outboards.
This short ram (ROS) kit serves the compact trim cylinder design used on numerous Mercury Racing applications spanning both the legendary 2.5L two-stroke era and the newer Mercury Racing ROS 4-stroke outboards.
Depending on model year and parts catalog revision, many boat owners and technicians may also recognize the earlier repair kit number 79879A1, which has largely been superseded by Mercury's newer 8M-series service numbering.
Why Trim Cylinder Seals Matter
Hydraulic trim systems operate under significant pressure while constantly being exposed to heat, vibration, UV exposure, water intrusion, and repeated cycling. Over time, internal seals naturally wear, harden, or lose elasticity.
Common symptoms of worn trim cylinder seals include hydraulic fluid leakage, trim bleed-down while underway, slow trim response, reduced holding pressure, or inconsistent operation.
Replacing worn seals restores hydraulic integrity and is often far more economical than replacing an entire trim cylinder assembly.
Mercury Racing and High-Performance Applications
This repair kit is commonly associated with Mercury Racing single-ram trim systems found on high-performance V6 outboards, including:
- Mercury Racing 260 EFI
- Mercury Racing 260 Offshore
- Mercury Racing 280 ROS
- Mercury Racing 300 Drag
- Mercury Racing S3000
- Mercury Racing 200 ROS 3.4L V6
- Mercury Racing 300 ROS 4.6L V8
These engines powered a wide range of offshore race boats, drag boats, Mod-VP boats, lake-race boats, and other high-performance applications utilizing Mercury's proven single-ram trim architecture.
Service Recommendations
Trim cylinder seal replacement is often performed during engine restoration projects, offshore rigging upgrades, hydraulic system maintenance, or whenever fluid leakage becomes visible around the trim ram shaft.
Because trim angle directly affects boat attitude, propeller efficiency, acceleration, and high-speed stability, maintaining proper trim system performance is important for both reliability and handling.
Many racers and performance boat owners rebuild trim cylinders proactively during offseason maintenance to avoid unexpected hydraulic failures during operation.
The Mercury OEM 8M0244476 Short Trim Ram Repair Kit remains an important service component for maintaining the performance and reliability of Mercury Racing hydraulic trim systems.
Whether rebuilding the trim cylinder on a classic 260 EFI, 280 ROS, 300 Drag, or a newer 200 ROS or 300 ROS platform, replacing worn seals helps restore proper hydraulic operation and extend the life of the trim system.
For Mercury Racing owners, proper trim function is critical to performance, safety, and drivability. Maintaining the trim cylinder with genuine Mercury service components helps ensure reliable operation both on the race course and on the water.
Genuine Mercury OEM Part Number: 8M0244476
Common Earlier Reference Number: 79879A1