Flat Idler Pulley AM146880 for John Deere X304 X310 X320 X350 LTR155 LTR166 Sabre 1542 1742 Scotts S1642 S1742 (1 Pack)

What It Is

The AM146880 flat idler pulley is a replacement guide pulley that routes the mower deck drive belt on select John Deere, Sabre, and Scotts lawn tractors. It reduces belt friction and maintains proper belt tension during cutting.

Fitment & Compatibility

Check your deck size and model. This pulley fits John Deere X300 series (X304, X310, X320, X350) and LTR155, LTR166, plus Sabre 1542, 1742 and Scotts S1642, S1742. Confirm your mower deck is 42-inch or 48-inch – this pulley is not for 54-inch decks. The OEM part number is AM146880; this is an aftermarket replacement. Measure your old pulley’s outside diameter (typically 3.5 inches) and bearing bore (usually 5/8 inch) to verify. If your deck uses a different idler design (e.g., spring-loaded vs. fixed), this flat idler will not work.

Key Things to Know

• Quality: Budget-friendly aftermarket part. Some users report slightly noisier operation than OEM, but it holds up for normal residential use. Check for smooth bearing rotation before installing.
• Installation: Moderate difficulty – you’ll need to remove the deck, release belt tension, and swap the pulley. A socket set and possibly a puller for stubborn pulleys are required. Expect 30–60 minutes.
• Common gotcha: The pulley may come with a different shoulder height than OEM. If your belt rides too high or low, you may need to add a washer as a spacer. Inspect the belt for wear first – a worn belt can cause premature pulley failure.
• Compatibility nuance: Some Sabre/Scotts models use a slightly different belt routing. Double-check your deck diagram before buying.

Should You Buy It

If you need a cheap, functional replacement for a worn idler pulley on your 42- or 48-inch John Deere X300 series or compatible Sabre/Scotts mower, this is a solid budget pick. It’s not for heavy commercial use, but for home lawn care, it’ll get you cutting again without the OEM price tag. Just verify your deck size and pulley measurements first.