Maintaining a Mercury Racing R-Series V8 or Mercury Verado V8 outboard at factory specifications requires more than oil changes. Mercury engineers have specified complete 300-hour service intervals to protect power, cooling efficiency, and corrosion resistance.
The official Mercury OEM 300-Hour Maintenance Kit — Part Numbers 8M00149932 (R-Series Racing applications) and 8M0149932 (Verado / SeaPro applications) — provides all of the OEM-validated components in one package. Available from Buckshot Racing #77 LLC, this kit is the benchmark for high-performance outboard service.
Kit Fittment
R-Series Mercury Racing: These are high-performance naturally aspirated V8 outboards — the 250R and 300R — designed for offshore racing, high-speed bass boats, and performance craft. The “R” signifies Racing, with elevated RPM limits, specialized gearcase options (Sport Master, Torque Master), and aggressive calibration.
Verado V8 Series: Mercury’s premium luxury and commercial platform, the 4.6 L V8 Verado line, produces 250–300 HP. Verado engines focus on smoothness, durability, and integrated AMS (Advanced MidSection) technology. Though tuned differently than Racing R-Series, Verado engines share much of the same 4.6 L V8 architecture.
OEM Part Numbers (8M00149932 and 8M0149932) — For the Mercury Racing 250R and Mercury Racing 300R Racing applications; Mercury Marine Verado V8 250–300 HP and SeaPro V8.
Mercury Racing R-Series V8
Mercury Racing 250R V8 4.6 L
Mercury Racing 300R V8 4.6 L
Verado 250 HP V8 (4.6 L AMS)
Verado 300 HP V8 (4.6 L AMS)
SeaPro 250–300 HP V8 (4.6 L commercial-duty platform)
Complete OEM Component Inventory
Each Mercury OEM 300-Hour Service Kit includes factory-specified components, eliminating the risk of aftermarket substitutes. The 8M0149932 Verado kit inventory (which mirrors the R-Series kit content) includes:
Oil Filter 35-8M0123025
Fuel Filter 35-8M0106635
Oil Drain Seals 26-8M0204693
Spark Plugs (NGK LKAR7C-09) 33-8M0204737
Thermostat 8M0162139
Alternator / Serpentine Belt 57-8M0218433
Hose Clamp 54-888988008
Water Pump Repair Kit 47-8M0205803
Anti-Vent Plate Anode 97-8M0137814
Screw M10 × 10-8M0142850
Plug Screws 10-8M0142878
External Anodes 97-893404
Screw M6 × 14 10-4000327
Gearcase Anode 97-880653
Bolts 10-889543016
Flat Washers 12-8M0161430
Note: Mercury engine oil and gear lube are required but not included in the kit.
Why Mercury Recommends the 300-Hour OEM Kit
1. Precision Filtration
The OEM oil filter 35-8M0123025 and fuel filter 35-8M0106635 are engineered for the R-Series and Verado fuel delivery systems. After 300 hours, fuel varnish, oil carbon, and micro-particulates require replacement filtration to maintain oil pressure and injector performance.
2. Cooling Reliability
The 47-8M0205803 water pump kit and 8M0162139 thermostat restore factory cooling efficiency. Impeller degradation is the number one cause of overheating in high-performance outboards. At 300 hours, a complete pump refresh is mandatory.
3. Ignition System Integrity
Using the factory-spec NGK LKAR7C-09 spark plugs 33-8M0204737 preserves Mercury’s ignition mapping. Substituting non-OEM plugs risks detonation under high RPM.
4. Corrosion Protection
Factory anodes 97-8M0137814, 97-893404, and 97-880653 are designed to balance galvanic load on the V8’s aluminum castings and gearcase. At 300 hours, refreshing anodes ensures continued corrosion resistance in saltwater conditions.
5. Accessory Reliability
The 57-8M0218433 alternator belt provides charging reliability for AMS and high-demand electrical systems. Belt stretch or slippage can compromise charging and steering assist on Verado AMS units.
Technical Benefits of the OEM Kit Over Aftermarket Alternatives
Mercury’s 300-hour kits are engineered as system-level solutions. Unlike aftermarket bundles that approximate component lists, the OEM 8M00149932 / 8M0149932 kits guarantee:
Exact material specifications — from gasket rubber durometer to impeller vane flexibility.
Correct torque hardware — OEM bolts, screws, and washers prevent over- or under-torque failures.
Serial number matching — components verified against current production runs, ensuring compatibility with updated casting revisions.
Warranty preservation — using non-OEM components risks Mercury Racing and Verado warranty coverage.
Buckshot Racing #77 LLC provides genuine Mercury OEM parts. Performance boaters and offshore racers rely on Buckshot Racing for fast fulfillment, direct technical support, and confidence that every part in the kit is factory-validated.
For technical support, contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com