Muffler Assy Gx340-390
Muffler Assy Gx340-390
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- Item# 5741
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Muffler Assembly for GX340-390 Engines - Quiets Down a Loud Rig
This is a complete muffler assembly for GX340 and GX390 engines, the powerplants behind many commercial pressure washer skids. When the original can rusts out or the baffles rattle loose, this bolts on and brings the exhaust note back down. It's in stock at Sun Brite Supply in Gaithersburg, MD.
A blown muffler makes a rig miserable to run and rough on your ears all day. Swapping the whole assembly beats patching a rusted can, and it's a quick job during a seasonal tune-up. If your GX340 or GX390 is getting loud, this is the fix.
Where Contractors Use This Muffler Assembly
Application and Compatibility
This component integrates into standard commercial pressure washing systems using industry-standard connections. Verify the specifications listed below against your existing equipment before ordering. Thread sizes, pressure ratings, and flow capacities must match your system for safe, leak-free operation. If you're not sure about compatibility, call (301) 519-9274 - we match parts to machines every day.
Contractor-Grade Quality
There's a real difference between professional equipment and consumer-grade alternatives sold at hardware stores. Consumer parts are built to a price point - they work fine for the homeowner who pressure washes their deck once a year. But put those same parts on a commercial rig running 8 hours a day, 5 days a week, and they fail fast. This pressure washer part is built for that daily grind. The materials, tolerances, and construction are designed for thousands of hours of commercial operation. That's why contractors come to Sun Brite Supply instead of buying online from unknown vendors - we carry the brands and specs that working professionals trust.
Installation and Setup
Verify Compatibility
Check the specifications against your existing equipment. Thread sizes, pressure ratings, and flow capacities must match for safe operation.
Install According to Specs
Follow the manufacturer's installation guidelines. Use appropriate thread sealant on pipe connections. Don't overtighten fittings.
Test Under Pressure
After installation, test at low pressure first. Check all connections for leaks before running at full operating pressure.
Compatible With
Specifications
| Product Type | Engine Muffler |
| Ships From | Gaithersburg, MD |
Maintenance and Troubleshooting
Inspect this component during your regular maintenance routine. Check for wear, leaks, corrosion, and proper operation. Replacing worn parts on schedule prevents mid-job failures that cost you time and money.
When to Replace vs. Repair
If this pressure washer part shows signs of wear but is still functional, a rebuild kit or replacement seals may extend its service life at a fraction of the full replacement cost. However, if you see cracks, cross-threading, severe corrosion, or complete failure under pressure, replacement is the safer and more economical choice. Call (301) 519-9274 and we'll help you decide. Always follow OSHA equipment safety standards when working with high-pressure equipment.
Frequently Asked Questions
Need Help Choosing the Right Part?
30+ years of industry experience. We match parts to machines every day.
Why Buy From Sun Brite Supply?
Sun Brite Supply has served pressure washing contractors from our Gaithersburg, MD location since 2011. We stock the professional-grade parts and equipment you won't find at big box stores. Every in-stock order ships within 24 hours. Local customers can pick up the same day. Call (301) 519-9274 and talk to someone who knows this equipment - not a call center.