New Flat Idler Pulley 690452 91801 91801MA 720920 774089MA 690452MA Compatible with Murray 23238 423238MA 38608A 9-35500 9-40620 & Grasshopper 393225 393225

What It Is

This flat idler pulley (cross-references: 690452, 91801, 91801MA, 720920, 774089MA, 690452MA) is a replacement part for the mower deck belt tensioning system on select Murray and Grasshopper riding mowers. It keeps the drive belt tight as the blades spin, preventing slippage and belt wear during cutting.

Fitment & Compatibility

Before buying, verify three things:

• Deck size & model: Fits Murray decks using OEM part numbers 23238, 423238MA, 38608A, 9-35500, 9-40620, and Grasshopper 393225, 393225. Common on 38–46” decks, but not all Murray or Grasshopper decks—check your mower’s model number against these.
• OEM vs aftermarket: This is an aftermarket replacement, not OEM Murray. It’s a direct fit for the listed OEM part numbers, but tolerances can vary slightly. If you need exact factory specs, stick with OEM.
• Measurements: Standard 3/8” bore (for a 3/8” shaft), 4” outer diameter, 3/8” belt width. Measure your old pulley’s bore, OD, and belt groove width to confirm match. Most flat idlers use a 3/8” bore, but some Grasshopper decks use 1/2” – measure first.

Key Things to Know

• Quality: Most buyers report it holds up fine for residential use. It’s a basic steel pulley with a sealed bearing—not heavy-duty commercial grade, but adequate for typical homeowner mowing.
• Installation difficulty: Easy. Remove the old pulley (usually one bolt/nut), slide the new one on, and re-tension the belt. No special tools needed.
• Common gotcha: The bearing is sealed and non-serviceable—if it fails later, you replace the whole pulley. Also, the belt groove width must match your belt; a mismatch causes premature wear.
• Price point: At $12.25, it’s cheaper than OEM (often $20–30) and has solid reviews (4.6/5 from 35 ratings). Good value if fitment checks out.

Should You Buy It

Buy this if you need a budget-friendly, direct-fit replacement for a Murray or Grasshopper deck flat idler pulley and you’ve confirmed the bore, OD, and belt groove match your old part. It’s not for commercial use or oddball decks, but for typical homeowner repairs, it’s a reliable, low-cost fix.