The reed block gasket is a small but important sealing component on a Mercury Marine or Mariner V6 two-stroke outboard. Located between the reed block, intake manifold, and front half assembly, this gasket helps seal the intake tract so the engine can maintain proper crankcase pressure, clean airflow, and consistent air-fuel delivery.
 
Whenever you are replacing reeds, removing reed cages, servicing the intake, or rebuilding a 2.0L, 2.4L, or 2.5L Mercury V6 powerhead, the reed block gasket should be inspected and replaced as needed. Reusing old, compressed, torn, fuel-soaked, or damaged intake gaskets can create air leaks that affect idle quality, throttle response, fuel mixture, and overall engine reliability.
 
These gaskets are commonly used on select Mercury 135 HP, 150 HP, 175 HP, and 200 HP V6 two-stroke outboards, along with popular performance models such as XR2, XR4, XR6, XRi, 200 Pro Max, SportJet 190, SportJet 210, SST-120, and APBA / Formula-style race applications using compatible reed plate and front-half configurations.
 
Why Reed Block Gaskets Matter
 
A Mercury V6 two-stroke depends heavily on crankcase sealing and intake signal. Unlike a four-stroke engine, the crankcase is part of the intake pumping system. Air leaks around the reed block or intake gasket can create lean conditions, uneven idle, hesitation, poor acceleration, hard starting, and inconsistent cylinder-to-cylinder fuel delivery.
 
A properly sealed reed block helps the reeds respond correctly to pressure pulses inside the crankcase. This supports cleaner low-speed operation, better throttle response, and more predictable fuel delivery. On higher-performance Mercury engines, including Pro Max, XRi, modified 2.5L builds, SST-120, SportJet, and race-prepped V6 outboards, intake sealing is especially important because small air leaks can become serious problems at high RPM.
 
Mercury Reed Block Gasket Options
 
Mercury used different intake and reed block arrangements across the V6 two-stroke family. The correct gasket depends on the engine’s front-half style, reed cage design, reed plate, and model year.
 
1) Gasket 27-935361 is used on select 2.0 Liter vertical front Mercury V6 two-stroke outboards, commonly associated with earlier Mercury and Mariner V6 applications from approximately 1976–1989.
 
2) Gasket 27-967611 is used on select 2.0L and 2.4 Liter horizontal front Mercury V6 two-stroke outboards, commonly associated with many Mercury / Mariner V6 applications from approximately 1978–1990.
 
3) Gasket 27-146972 is used on many select 2.0L and 2.5 Liter horizontal front Mercury V6 two-stroke outboards, including later XRi, EFI, Pro Max, 4-petal, and 5-petal reed block applications.
 
4) Gasket 27-146973 is also used on select 2.5 Liter Mercury Optimax DFI SportJet 200 HP applications when matched to the 4-petal rubber-coated reed blocks and intake configuration.
 
These categories are helpful for identifying the correct gasket, but Mercury V6 engines were produced in many variations. Always verify your gasket by engine serial number, reed plate, front-half style, reed cage layout, and original gasket shape before ordering.
 
4-Petal and 5-Petal Reed Applications
 
Mercury V6 outboards used both 4-petal and 5-petal reed configurations depending on engine model, year, and performance package. The reed block gasket must match the reed cage and intake layout. A gasket that lines up with the bolt holes but does not correctly match the reed opening can disrupt airflow or create sealing issues.
 
These gaskets are commonly used during reed upgrades, steel reed replacement, composite reed installation, intake service, EFI service, carburetor work, and complete powerhead rebuilds. They are suitable for many stock and performance Mercury V6 outboards when the correct style is selected.
 
OEM and Aftermarket Cross References
 
Common Mercury and aftermarket gasket references include 27-935361, 935361, 27-967611, 967611, 27-96761 1, 96761, 27-146972, 14-69723, 18-0644, 18-2501, 18-2510, 9-60055, 9-60060, 37530, 508792, 516-26, 516-33, 67738, 10-68418, 10-684, 32-450, and 50-8847.
 
Because some numbers may refer to different gasket styles or related intake gasket applications, customers should select the gasket that matches their exact engine configuration rather than relying on one cross-reference alone.
 
Installation Notes
 
When replacing reed block gaskets, clean both sealing surfaces carefully and remove all old gasket material without damaging the aluminum. Inspect the reed cages, reeds, screws, intake surface, and crankcase sealing area before reassembly. Any chipped reed, loose screw, warped cage, or damaged sealing surface should be corrected before the engine is run.
 
The gasket should normally be installed dry unless the service procedure or engine builder specifies otherwise. Avoid excess sealant around reed blocks because loose sealant can enter the intake path. Fasteners should be tightened evenly and to the proper specification for the engine.
 
Buckshot Racing #77 Tech Tip
 
If a Mercury V6 two-stroke has a hanging idle, lean sneeze, poor throttle response, or one cylinder that looks different from the others, do not overlook the intake gaskets and reed blocks. A leaking reed block gasket can mimic carburetor, EFI, ignition, or reed problems.
 
For best results, replace the reed block gaskets any time the intake or reed cages are removed. This is inexpensive insurance during a reed upgrade, carb rebuild, EFI service, SportJet service, or complete 2.0L, 2.4L, or 2.5L Mercury V6 powerhead rebuild.
 
Final Thoughts
 
Buckshot Racing #77 offers selected Mercury V6 Reed Block Intake Gaskets for many 2.0L, 2.4L, and 2.5L Mercury / Mariner two-stroke outboards, including popular 135 HP, 150 HP, 175 HP, 200 HP, XR2, XR4, XR6, XRi, 200 Pro Max, SportJet 190, SportJet 210, SST-120, APBA / Formula race engines, and select 2.5 Liter Optimax DFI SportJet 200 applications using 27-146973.
 
Choose the correct vertical front, horizontal front, 4-petal, or 5-petal gasket style for your engine and verify fitment before installation. A proper intake seal helps protect the engine, improve consistency, and keep your Mercury V6 running the way it should.