EZYPAK Dual Inlet Muffler for Twin-Cylinder Lawn Tractors — Direct-Fit Replacement for Husqvarna 539131604, Heavy-Duty Corrosion-R

EZYPak 539131604 is a direct-fit dual-inlet muffler engineered to replace worn or damaged twin-cylinder exhausts on select Husqvarna and Craftsman zero-turn and lawn tractor models.

This heavy-duty muffler provides a precise fit for machines that accept Husqvarna part number 539131604 and many equivalent models from Craftsman, Jonsered and Husqvarna. It’s built to withstand high engine temperatures and outdoor exposure while reducing noise and maintaining exhaust flow. The design focuses on durability and straightforward installation so you can get the mower back into service quickly.

Which mower models will this muffler fit?

The EZYPak 539131604 is made as a replacement for Husqvarna part 539131604 and matches the mounting pattern and inlet arrangement of many twin-cylinder zero-turn tractors. It’s compatible with a broad list of models from Husqvarna, Craftsman and Jonsered commonly equipped with twin-cylinder engines.

• Directly fits Husqvarna models that use part 539131604 (e.g., MZ5424S, MZ5425S series).
• Compatible with Craftsman model 917277730 and Jonsered Z54R variants.
• Works with EZ/FD/LSZ series decks such as EZ 4824, EZ 5224, FD61M and LSZ 5422.
• Check your OEM part number and inlet layout before ordering to confirm compatibility.

How does this muffler affect noise and exhaust performance?

This muffler is engineered to reduce engine noise compared with a damaged or rusty OEM unit while keeping exhaust backpressure within acceptable limits for twin-cylinder engines. It focuses on quieter operation without compromising normal engine breathing when installed correctly.

• Dual inlet design aligns with twin-cylinder exhaust ports to balance flow.
• Internal baffling reduces high-frequency engine noise for a more comfortable ride.
• Constructed to withstand heat so performance remains stable over time.
• Not a performance upgrade—intended as a like-for-like replacement for stock mufflers.

What materials and construction features ensure long-term durability?

The muffler uses robust metal alloys and a protective finish to resist corrosion and degradation from heat cycles and exposure to moisture. Its thicker shell and reinforced welds help it last longer than thin aftermarket alternatives.

• Heavy-gauge steel body resists dents and heat fatigue.
• Rust-resistant coating extends service life in outdoor conditions.
• Reinforced inlet flanges and mounts handle vibration common to zero-turn tractors.
• Designed to match OEM mounting points for secure attachment.

How difficult is installation and what hardware is required?

Installation is straightforward for a person with basic hand tools and typically takes about 15–20 minutes. The muffler’s mounting holes are prepared for self-tapping bolts, so you may need to provide bolts or use existing hardware depending on your machine.

• Expect a quick swap using common wrenches and a screwdriver or impact driver.
• Self-tapping bolts are recommended for a tight fit; fasteners not included.
• Ensure exhaust gasket and flange surfaces are clean before assembly.
• If unsure, have a small shop or technician perform installation for safety.

Who is this for: This EZYPak muffler suits owners of Husqvarna, Craftsman and Jonsered zero-turn or lawn-tractor models that require a 539131604-style dual-inlet replacement. It’s intended for homeowners, landscapers and small-property managers seeking a durable, OEM-compatible exhaust replacement that reduces noise and restores reliable operation without engine modifications.