Pipe Plug for Universal Marine Applications – 1/4" NPT Brass Fitting
This 1/4" NPT brass pipe plug is designed for universal marine applications, providing a reliable seal for threaded pipe openings across a wide range of engines and systems. Engineered from durable brass material, this fitting ensures corrosion resistance and long-lasting performance in harsh marine environments.
This plug directly replaces Mercury Quicksilver 22-36382, Sierra 18-4256, and Mallory 9-40545, offering broad cross-brand compatibility. It has been used in applications including Mercruiser 7LX 4BBL GM 350 V-8 engines (1996 model year) and many other marine systems requiring 1/4" NPT threaded plugs.
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Material: Brass construction for superior corrosion resistance
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Thread Size: 1/4" NPT (0.250-18 threads)
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Universal fit across multiple marine engine brands and models
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| Mercury Quicksilver |
22-36382 |
| Sierra |
18-4256 |
| Mallory |
9-40545 |
Compatible Engine Models
This pipe plug is compatible with universal marine applications requiring a 1/4" NPT brass fitting. It has been confirmed to fit Mercruiser 7LX 4BBL GM 350 V-8 (1996) and many other marine engines and systems across multiple brands.
Technical Specifications
| Specification |
Value |
| Thread Size |
1/4" NPT |
| Thread Specification |
0.250-18 |
| Material |
Brass |
| Application |
Universal Marine |
Package Contents
Your purchase includes:
- 1 × Pipe Plug (1/4" NPT Brass)
The package contains all the parts shown in the picture.
Installation Guide
- Ensure the engine is off and the system is depressurized before beginning installation.
- Clean the threaded opening thoroughly to remove any debris, old sealant, or corrosion.
- Apply a thin layer of marine-grade thread sealant or Teflon tape to the plug threads in a clockwise direction.
- Hand-thread the pipe plug into the 1/4" NPT opening, turning clockwise until finger-tight.
- Use an appropriate wrench to tighten the plug an additional 1 to 1.5 turns beyond hand-tight. Do not over-tighten, as this may damage the threads or crack the fitting.
- Wipe away any excess sealant from the exterior of the fitting.
- Verify that the plug is seated securely and check for any visible gaps or misalignment.
- Restart the system and inspect for leaks around the plug. If leakage occurs, depressurize and re-tighten slightly.
Troubleshooting & FAQ
Q: How do I confirm this pipe plug will fit my marine engine or system?
A: Verify that your application requires a 1/4" NPT brass pipe plug. Check your engine's parts diagram or compare with the OEM part numbers listed (Mercury 22-36382, Sierra 18-4256, Mallory 9-40545). Ensure the thread size matches before installation.
Q: What if the plug doesn't seal properly after installation?
A: First, verify you've applied appropriate marine-grade thread sealant or Teflon tape. Ensure the threads in the receiving port are clean and undamaged. If leakage persists, remove the plug, inspect both male and female threads for damage, and re-apply sealant before reinstalling.
Q: Can I reuse this brass pipe plug after removal?
A: While brass plugs are durable, reuse depends on thread condition. Inspect the threads carefully after removal; if they show wear, deformation, or damage, replace the plug. Always apply fresh thread sealant when reinstalling.
Q: Why choose brass material for marine applications?
A: Brass offers excellent corrosion resistance in saltwater and freshwater environments, superior to steel fittings. It also provides a good balance of strength and workability, reducing the risk of thread stripping during installation.
Q: Is this an OEM part or aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.