Replaces 331737B Mulching Blade for 21" Cut Craftsman/Husqvarna/Poulan Mowers Replaces 165833, 175064, 189028, 406712, 176135, 159267 & Many Others,Black

What It Is

This is a replacement mulching blade designed for 21-inch cut walk-behind mowers from Craftsman, Husqvarna, and Poulan. It replaces multiple OEM part numbers (331737B, 165833, 175064, 189028, 406712, 176135, 159267) and is intended for use on mowers with a single-blade, 21-inch cutting deck.

Fitment & Compatibility

Before buying, verify these three things:

• Deck size: Your mower must have a 21-inch cutting deck. Measure the deck width if unsure.
• Blade length: The blade is 21 inches from tip to tip. Measure your old blade’s length and center hole diameter (typically 7/8-inch or 1-inch). This blade uses a standard 7/8-inch center hole and a 5-point star drive pattern, but double-check your spindle’s shape.
• Model/brand: Fits most Craftsman, Husqvarna, and Poulan walk-behinds with a 21-inch deck. Check your mower’s model number against the listed OEM numbers. It may also fit some MTD, Murray, or Yard Machines models—cross-reference your old part number.

Pro tip: Remove your current blade and compare its shape, hole size, and lift profile to this one. Aftermarket blades can vary slightly in thickness or curvature, which may affect mulching performance.

Key Things to Know

• Quality: Steel construction with a black coating for rust resistance. Expect comparable durability to OEM blades, but not premium high-lift or gator-style blades.
• Installation difficulty: Easy with basic tools—socket wrench, torque wrench (recommended 30-45 ft-lbs). Always disconnect the spark plug and tip the mower with the carburetor side up.
• Common gotchas: Ensure the blade is oriented with the curved side pointing up toward the deck for proper mulching. A sharpened edge is included, but you may need to balance the blade on a balancer after installation.
• Mulching vs. bagging: This blade is optimized for mulching (fine clippings). If you frequently bag or side-discharge, consider a standard lift blade instead.

Should You Buy It

Yes, if you need a direct replacement for a worn mulching blade on a 21-inch Craftsman, Husqvarna, or Poulan mower and want a reliable aftermarket option at a fair price. Skip it if your mower has a non-standard spindle or you require a high-performance gator blade for heavy-duty mulching.