The Buckshot Racing #77 Mercury 27-841220 Reed Plate Intake Gasket is the highest-quality OEM-equivalent replacement gasket designed for compatible Mercury 3.0L and 3.2L V6 two-stroke outboards. It installs between the reed plate assembly and crankcase and helps maintain the crankcase seal required for proper two-stroke intake operation.
Whenever you remove the reed plate, reed cages, reed valves, or related intake components, replace the gasket rather than reusing the old compressed gasket. Even a small leak at this joint can disrupt crankcase pressure and affect idle quality, throttle response, fuel delivery, and overall engine performance.
This gasket replaces Mercury 27-841220 and the earlier superseded 27-804680 design. It uses AFM, Advanced Fiber Material, providing a durable sealing surface with good resistance to fuel, oil, heat cycling and vibration.
Why the Reed Plate Gasket Matters
Mercury two-stroke engines rely on alternating crankcase pressure and vacuum pulses to move the incoming air-fuel charge through the reed valves and into the cylinders. The reed plate and crankcase must seal correctly for that process to work as designed.
If the gasket becomes damaged, hardened, fuel-soaked or permanently compressed, outside air can enter the intake side of the engine. This can contribute to poor idle quality, hesitation, lean running, inconsistent fuel delivery or reduced throttle response.
For this reason, the reed plate gasket should be treated as a normal replacement item whenever the intake assembly is removed.
OEM-Equivalent AFM Construction
The Buckshot Racing #77 gasket is designed as an OEM-equivalent replacement for the original Mercury sealing profile and mounting pattern.
AFM construction provides a stable sealing surface under repeated heat cycles and the constant pressure pulsing found inside a two-stroke crankcase. It also offers strong resistance to the fuel and oil exposure common in Mercury EFI and DFI intake systems.
This makes the gasket well suited for both stock service work and high-performance rebuilds where intake sealing must remain consistent.
Mercury 3.0L & 3.2L Applications
The 27-841220 reed plate intake gasket is used across many compatible Mercury 3.0L and 3.2L V6 two-stroke engines.
Typical applications include selected 200 HP, 225 HP, 250 HP and 300 HP Mercury outboards in EFI, Optimax DFI, Pro XS, Sport XS and Mercury Racing configurations.
It is also commonly used on compatible 300X and 3.0L-based performance builds, along with certain 3.2L stroker combinations using the same reed plate and crankcase gasket pattern.
Because Mercury used several front-half and intake arrangements over the years, the best fitment check is the engine serial number, original gasket number and reed plate configuration.
Cross-Reference Part Numbers
This OEM-equivalent gasket is commonly cross-referenced to Mercury 27-841220, 841220, 27-804680 and 804680, along with aftermarket references including 850283, Sierra 18-2707, 10-2707, 2707 and 516-40-01.
The 27-841220 number is the later Mercury reference, while 27-804680 is commonly encountered in older parts catalogs and service documentation.
Recommended During Reed Service
Whenever the reed plate is removed, inspect the reed cages, petals, mounting hardware and mating surfaces before reassembly.
Whether installing original-style reeds, composite performance reeds or complete replacement reed cages, fitting a fresh intake gasket at the same time helps reduce the chance of a repeat teardown caused by an intake-side air leak.
On older Mercury 3.0L and 3.2L engines, this is especially important because the original gasket may already be hardened, distorted or permanently compressed after years of service.
Buckshot Racing #77 Installation Tech Tip
Before installation, remove all old gasket material from the reed plate and crankcase without gouging the aluminum surfaces. Inspect both mating faces for corrosion, nicks or distortion.
Install the new gasket in the correct orientation and use the Mercury factory service procedure for the exact engine when tightening the reed plate. Start all fasteners first, then tighten evenly so the plate seats flat and the gasket is compressed uniformly.
The Buckshot Racing #77 OEM-Equivalent Mercury 27-841220 AFM Reed Plate Intake Gasket is a simple but important service component for compatible 3.0L and 3.2L Mercury V6 two-strokes. It replaces the earlier 27-804680 gasket and is an excellent choice for reed service, intake repairs and complete Mercury powerhead rebuilds.
Contact Mike Hill at +1-714-697-1716 or mike@buckshotracing77.com for technical support.