Exhaust Flapper – Fits MerCruiser Stern Drives 2.5L, 3.0L, 3.7L, V8 Jackshaft (Replaces 60930, 18-2727)
Exhaust Flapper – Fits MerCruiser Stern Drives 2.5L, 3.0L, 3.7L, V8 Jackshaft (Replaces 60930, 18-2727) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Exhaust Flapper – Fits MerCruiser Stern Drives 2.5L, 3.0L, 3.7L, V8...
Product Details
This Exhaust Flapper with Grommets is designed to prevent water from entering the engine through the exhaust system on MerCruiser Stern Drive models. It is compatible with 4-Cylinder 2.5L, 3.0L, and 3.7L engines from 1982–1998, as well as V8 engines with a Jackshaft from 1985 and newer.
It serves as a direct cross-reference for Mercury MerCruiser part 60930/25-43809, Sierra 18-2727, and Mallory 9-42800.
- Engineered for direct-fit installation.
- Made with premium metal and rubber for durability in marine environments.
- Includes essential grommets for a complete replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury MerCruiser | 60930 |
| Mercury MerCruiser | 25-43809 |
| Sierra | 18-2727 |
| Mallory | 9-42800 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This flapper fits specific MerCruiser stern drive engines as listed below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | 4-Cylinder | 2.5L | 4-Stroke | 1982–1998 | 60930 | |
| MerCruiser | 4-Cylinder | 3.0L | 4-Stroke | 1982–1998 | 60930 | |
| MerCruiser | 4-Cylinder | 3.7L | 4-Stroke | 1982–1998 | 60930 | |
| MerCruiser | V8 with Jackshaft | Various | 4-Stroke | 1985–Up | 60930 |
Technical Specs
- Product Type
- Exhaust Flapper Shutter
- Installation
- Direct Replacement
- Fuel Type
- Gasoline
- Housing Material
- Premium Metal and Rubber
- Dimensions
- 79 mm × 94 mm (3.1" × 3.7") [width × length]
- Other Technical Attributes
- High hardness, durable construction
What’s in the Box
- 1 x Exhaust Flapper (equivalent to 60930)
- 2 x Grommets
Installation Notes
- Disconnect the negative battery terminal for safety.
- Gain access to the exhaust Y-pipe. This may require removing the stern drive or exhaust bellows.
- Carefully remove the old grommets and the worn or damaged exhaust flapper from the Y-pipe.
- Thoroughly clean the mounting surfaces inside the Y-pipe where the grommets and flapper sit.
- Install the two new grommets into their designated holes in the Y-pipe.
- Insert the new exhaust flapper, ensuring its tabs fit securely into the new grommets.
- Check that the flapper can move freely and creates a seal when closed.
- Reassemble all disconnected components in the reverse order of removal.
- Reconnect the battery, start the engine, and check for any exhaust leaks.
Troubleshooting & FAQ
How do I know if my exhaust flapper needs replacing?
Common signs include a rattling noise from the exhaust at idle, water in the engine oil (milky oil), engine hydrolock, or visible damage such as cracks or missing pieces on the old flapper during an inspection.
Will this fit my V8 engine?
This flapper fits specific MerCruiser V8 models that are equipped with a Jackshaft (from 1985 and newer). It does not fit standard V8 models that do not have a jackshaft configuration.
What is the purpose of an exhaust flapper?
The exhaust flapper is a critical one-way valve in your stern drive's exhaust system. It opens to allow exhaust gases to escape but closes to prevent water from flowing back into the engine, especially when the engine is off or at idle in the water.
How often should I replace the exhaust flapper?
Replacement intervals can vary based on usage (saltwater vs. freshwater) and operating hours. It is best practice to inspect them annually during routine maintenance and replace them every 2-3 years, or immediately if you notice any signs of wear, brittleness, or damage.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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