Air Silencer Gasket – Fits Johnson/Evinrude 40-50 HP (Replaces 321497)
Air Silencer Gasket – Fits Johnson/Evinrude 40-50 HP (Replaces 321497) 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
Air Silencer Gasket – Fits Johnson/Evinrude 40-50 HP (Replaces 321497)
Product Details
This aftermarket Air Silencer Gasket is designed for Johnson/Evinrude 40-50 HP, 2-Stroke outboard motors from the 1960s–1980s that use an air silencer box assembly. It creates a critical seal between the carburetor and the airbox to ensure proper engine performance.
It serves as a direct interchange for OMC part 321497, Sierra 18-0983, Mallory 9-60429, and GLM 35180.
- Installs directly between the carburetor and air silencer box.
- Made from durable composite gasket material to prevent air leaks.
- Ensures a proper seal to restore the correct engine air/fuel mixture.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC | 321497 / 0321497 |
| Sierra | 18-0983 / 18-0983-9 |
| Mallory | 9-60429 |
| GLM | 35180 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Johnson/Evinrude | 40HP-50HP | 40-50 | 2-Stroke | 1960s–1980s | 321497/0321497 | Air box silencer gasket |
Technical Specs
- Product Type
- Air Silencer Gasket
- Installation
- Direct fitment between carburetor and air silencer box
- Dimensions
- 9.31 in × 6.0 in × 1.13 in (approx. 236.5 mm × 152.4 mm × 28.7 mm)
- Weight
- 0.057 kg (0.125 lb)
- Material
- Gasket paper/composite
- Color
- Brown/tan
- Warranty
- Manufacturer standard parts warranty
What’s in the Box
- 1 x Air Silencer Gasket (Replaces 321497/0321497)
Installation Notes
- Disconnect the battery and ensure the engine is completely cool before starting.
- Locate and carefully remove the air silencer box cover and assembly from the carburetor.
- Remove the old, worn air silencer gasket and note its orientation.
- Thoroughly clean both the carburetor and silencer box mating surfaces. Ensure they are free of old gasket material, oil, and debris for a proper seal.
- Place the new gasket into position, aligning it perfectly with the mounting holes.
- Reinstall the air silencer box assembly and tighten all fasteners to the manufacturer's recommended torque specifications. Do not overtighten.
- Reconnect the battery and start the engine, listening carefully for any whistling or hissing sounds that would indicate an air leak.
Troubleshooting & FAQ
How do I know if my air silencer gasket has failed?
Signs of a bad gasket include a rough or unstable idle, engine stalling at low speeds, whistling or hissing sounds from the engine cowl, and reduced overall performance. These symptoms are caused by a vacuum leak, which allows unmetered air to disrupt the engine's air-fuel mixture.
Will this fit my specific Johnson 50 HP from 1975?
This part is specified for a broad range of 40-50 HP Johnson/Evinrude models from the 1960s to 1980s. However, it is critical to compare your old part to our product images and specifications to ensure a perfect match, as variations can exist.
Is any sealant required during installation?
Generally, this type of gasket is designed to be installed dry. Applying sealants can sometimes cause the gasket to slip or fail prematurely. Always follow your engine's service manual for the most accurate, model-specific recommendations.
The old part number is 321497, but this replaces 0321497. What's the difference?
OMC (the original manufacturer for Johnson/Evinrude) often used different prefix numbers for the same part over the years. Both 321497 and 0321497 refer to the identical component shape and function.
What is the purpose of an air silencer gasket?
It creates an airtight seal between the carburetor and the air silencer (or airbox). This prevents unmetered air from entering the engine, which would disrupt the carefully balanced fuel-to-air ratio and cause poor running conditions.
I see conflicting information online about this part. How can I be sure it's correct?
You are right; some databases misidentify this part. We have confirmed through multiple marine-specific sources that OMC 321497 is an air silencer gasket for Johnson/Evinrude outboards. Always trust the visual match between your old part and our photos over conflicting text descriptions from non-specialized databases.
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.
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