Exhaust Plate Gasket – Fits Mercury 175 HP V6 (Replaces 27-75909, 75909)
Exhaust Plate Gasket – Fits Mercury 175 HP V6 (Replaces 27-75909, 75909) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Product Details
This high-quality Exhaust Plate Gasket is engineered for Mercury Marine 175 HP V6 outboard engines with serial numbers 6618750 and below. It ensures a precise seal between the cylinder block and the mounting plate, preventing exhaust and water leaks.
This component serves as a direct replacement for Mercury part 27-75909 and provides an exact interchange for GLM 31870 and Sierra 18-0369.
- Installs between the cylinder block and mounting plate.
- Made from durable, high-temperature gasket material.
- Designed for use in gasoline marine engines.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| Mercury | 27-75909 |
| GLM | 31870 |
| Sierra | 18-0369 |
Engine & Model Compatibility
Confirm your engine model and serial number in the table below to ensure accurate fitment.
For Mercury Marine engines, it is critical to verify that your engine's serial number is 6618750 or lower, as specified.
| Brand | Model | Rated HP | OEM Part No. | Notes |
|---|---|---|---|---|
| Mercury | V6 | 175 (1750) | 27-75909 | For engines with s/n 6618750 & below |
Technical Specs
- Product Type
- Exhaust Plate Gasket
- Installation Location
- Cylinder Block to Mounting Plate
- Fuel Type
- Gasoline
- Material
- Gasket Material (Composition)
- Product Dimensions
- 13.0" x 10.0" x 1.13" (L x W x H)
- Application
- For Mercury 175 HP (1750) V6 s/n 6618750 & Below
What’s in the Box
- 1 x Exhaust Plate Gasket (Replaces 27-75909)
Installation Notes
- Disconnect the negative battery terminal to prevent electrical shorts.
- Drain the engine block of coolant to avoid spills.
- Remove any components obstructing access to the exhaust plate.
- Carefully unbolt and remove the exhaust plate, taking note of bolt order.
- Thoroughly clean both the engine block and plate surfaces. Remove all traces of the old gasket and any corrosion.
- Position the new gasket correctly, ensuring all bolt holes align perfectly.
- Reinstall the exhaust plate and tighten the bolts in a crossing pattern to the manufacturer's recommended torque specifications.
- Reassemble all previously removed components.
- Refill the coolant, reconnect the battery, and start the engine.
- Carefully inspect for any exhaust or water leaks around the newly sealed area.
Troubleshooting & FAQ
How do I confirm this gasket fits my specific engine?
This gasket is specifically for Mercury 175 HP V6 outboard engines with a serial number of 6618750 or lower. Always locate and verify your engine's serial number before purchasing to guarantee compatibility.
What are common symptoms of a failing exhaust plate gasket?
Signs of a bad gasket include engine overheating, water in the cylinders (hydrolock), a visible water or exhaust leak from the joint, reduced engine performance, or an unusual hissing sound from the engine block.
When should this gasket be replaced?
There is no set replacement interval. This gasket should be replaced any time the exhaust plate is removed for service or if signs of a leak are detected. It is a single-use part and should not be reused once compressed.
Is any sealant required during installation?
Generally, this type of gasket is designed to be installed dry. Applying sealants can sometimes interfere with its ability to seal properly. Always follow the specific instructions in your engine's service manual.
What is the difference between an OEM and an aftermarket part?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Our parts are manufactured in an ISO 9002 facility and are batch-inspected for quality and consistency.
What are your shipping speed and costs?
We ship worldwide quickly—typical transit time is 5–15 days. Standard shipping is free to most regions; expedited options and final costs will be displayed at checkout where available.
What warranty and return policies apply?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against 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 quality control.
Payment & Security
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