GHmarine Exhaust Flapper for MerCruiser 2.5L/3.0L/3.7L Stern Drives — Single Flapper with 2 Grommets, OEM-Quality Metal

GHmarine 60930 Exhaust Flapper with two grommets is a direct-fit replacement shutter for MerCruiser 2.5L, 3.0L and 3.7L stern drive exhausts, matching OE numbers MerCruiser 60930, Mallory 9-42800 and Sierra 18-2727.

This exhaust flapper assembly is designed to restore proper water/exhaust routing and reduce backflow in stern drive systems. Manufactured from hardened metal with rubber grommets included, it’s offered as an OEM-quality, cost-effective replacement to help maintain reliable engine exhaust performance. The part ships as a single flapper and two replacement grommets, ready for straightforward installation by a marine technician or experienced boater.

Will this flapper fit my MerCruiser 2.5L, 3.0L or 3.7L engine?

The GHmarine 60930 is built to match the factory dimensions and mounting points referenced by MerCruiser OE 60930 as well as cross-references Mallory 9-42800 and Sierra 18-2727. It is intended for use in the exhaust assembly of specified 2.5L, 3.0L and 3.7L stern drive engines.

• Compatibility: MerCruiser 2.5L, 3.0L, 3.7L stern drive exhaust systems
• OE matched: MerCruiser 60930 / Mallory 9-42800 / Sierra 18-2727
• Direct replacement: same mounting pattern and dimensions

How easy is it to install the exhaust flapper and grommets?

Installation is typically quick for anyone familiar with stern drive exhaust service; the flapper mounts to the exhaust tube and the rubber grommets secure the pivot points. Basic hand tools are usually sufficient, but consult your service manual or a mechanic if you’re unsure.

• Includes: 1 flapper + 2 grommets for a complete pivot rebuild
• Tools: common hand tools and possibly a marine sealant
• Time: often replaced within 30–60 minutes by a trained technician

What materials and durability can I expect from this replacement part?

GHmarine supplies the flapper in premium metal for structural strength plus rubber grommets engineered to resist water and heat exposure. The construction aims to mirror OEM hardness and wear characteristics so the part performs reliably under normal marine operating conditions.

• Body: high-hardness metal for long-lasting shutter action
• Grommets: durable rubber to reduce vibration and wear at pivot points
• Finish: corrosion-resistant treatment to withstand marine environments

What should I check after installing the new flapper?

After installation, verify the flapper opens and closes freely without binding, check for secure grommet seating, and inspect for exhaust leaks at the mounting area. Run the engine briefly at idle to ensure correct exhaust flow and re-tighten fasteners after the first run if needed.

• Function test: confirm smooth travel of the flap across operating range
• Leak check: look for exhaust or water seepage at the seal
• Re-torque: recheck hardware after initial engine run

Who is this for: Boat owners, marine technicians and parts resellers needing a dependable, budget-conscious replacement exhaust flapper for MerCruiser 2.5L, 3.0L and 3.7L stern drives. It’s aimed at anyone looking to restore correct exhaust operation with an OE-referenced component that includes the necessary grommets for a proper pivot repair.