The Crankcase Cork Strip Gasket, Mercury Part Number 27-11338 from Buckshot Racing #77, is a replacement sealing strip used during crankcase and powerhead service on classic Mercury and Mariner 2.0L, 2.4L, and 2.5L V6 two-stroke engines.
This cork strip is part of the crankcase sealing system and helps the assembled powerhead maintain the pressure and vacuum pulses required for proper two-stroke operation.
Because the Mercury V6 crankcase participates directly in moving the air-and-fuel charge through the reed system, maintaining an airtight crankcase is critical to idle quality, throttle response, and overall engine reliability.
The Mercury 11338 cork strip is also commonly identified under cross-reference numbers 10-686, 18-2513, 30890, 508849, 540-30, 67208, and 9-60049. These numbers are useful when identifying the correct gasket in Mercury, Mariner, and aftermarket rebuild catalogs.
Why the Mercury 11338 Cork Strip Matters
A Mercury V6 two-stroke does not use its crankcase simply as a structural housing. As the pistons travel through the cylinders, alternating pressure and vacuum pulses develop within the crankcase. Those pulses help move the incoming fuel-and-air mixture through the reed cages and toward the combustion chambers.
If an old 27-11338 crankcase cork strip becomes hardened, flattened, torn, or displaced, the crankcase can develop an air leak. Even a relatively small leak can disturb the pressure pulses and introduce unmetered air into the engine.
Possible symptoms include poor idle quality, a hanging idle, hesitation, inconsistent throttle response, lean running, or uneven cylinder performance. On a high-performance Mercury two-stroke, a significant air leak can also raise combustion temperature and increase the risk of piston or cylinder damage.
For that reason, old crankcase cork strips should not be reused during a powerhead rebuild.
Mercury 2.0L, 2.4L & 2.5L V6 Applications
The Mercury 11338 / 18-2513 crankcase cork strip is used across a broad range of Mercury and Mariner V6 two-stroke powerheads.
Applications include many 2.0L, 2.4L, and 2.5L V6 engines, including 135, 150, 175, 200, and ProMax 225 HP configurations. It is also commonly associated with performance families such as XR2, XR4, XR6, XRi, Laser EFI, SST-120, SST-140, Magnum, Pro Max 225, Bridgeport, 245 Carb, 260 EFI, 280 ROS, 300 Drag, and S3000, where the original crankcase design uses this style of cork sealing strip.
Because many older Mercury V6 engines have been rebuilt, modified, or assembled from components from different model years, the safest fitment check is always to compare the original crankcase sealing arrangement and gasket configuration before final assembly.
Two Cork Strips Required Per Engine
A complete Mercury V6 powerhead uses two crankcase cork strip gaskets. Each Mercury 11338-style cork strip is sold individually, so a complete engine rebuild requires a quantity of two.
This is an important detail when ordering a complete Mercury V6 rebuild package. One strip services only one side of the crankcase sealing arrangement.
Cross-Reference Part Numbers
The Buckshot Racing #77 crankcase cork strip is commonly identified by the following Mercury and aftermarket numbers: Mercury 11338, 10-686, 18-2513, 30890, 508849, 540-30, 67208, 9-60049, and others.
These numbers all help technicians and engine builders identify the correct Mercury V6 crankcase cork strip gasket when working from older service manuals, rebuild kits or aftermarket catalogs.
Add Loctite 518 for a Complete Mercury Crankcase Rebuild
Customers rebuilding a Mercury V6 powerhead can also add Loctite 518 Anaerobic Crankcase Sealant at checkout. The cork strips and Loctite 518 perform different sealing jobs and should not be confused.
The 11338 cork strips seal their designated crankcase strip locations, while Loctite 518 is used on close-fitting metal-to-metal crankcase flange surfaces where an anaerobic sealant is specified.
Loctite 518 is especially useful on precision-machined aluminum crankcase halves because it cures when confined between the mating metal surfaces and deprived of air.
It should not be used as a substitute for the cork strips.
Buckshot Racing #77 Rebuild Tech Tip
When replacing the Mercury 11338 crankcase cork strips, remove all remnants of the original cork and old sealant carefully. Avoid gouging or scratching the aluminum sealing surfaces.
Before final assembly, make sure the new strips sit evenly in their intended locations and are not stretched, twisted, or displaced. A mispositioned strip can create a leak even if the rest of the crankcase assembly is correctly sealed.
Whenever the crankcase is open, take the opportunity to inspect the reed cages, reed petals, crankshaft seals, bearings, sealing surfaces and intake components before the powerhead is reassembled.
A fresh pair of Mercury 11338 crankcase cork strips, combined with the correct anaerobic sealant on the machined crankcase surfaces where specified, provides a solid foundation for a reliable Mercury V6 rebuild.
The Buckshot Racing #77 Mercury V6 Crankcase Cork Strip Gasket 11338 is a simple but essential rebuild component for compatible Mercury and Mariner 2.0L, 2.4L, and 2.5L V6 two-stroke powerheads.
Two (2) strips are required per engine, and each strip is sold individually.
Contact Mike Hill at +1-714-697-1716 for tech support.