A deck belt that repeatedly jumps off is usually a symptom of another problem. Simply reinstalling or replacing the belt may not solve it.
Check these first
- Correct belt part number and dimensions
- Correct routing around every pulley and belt keeper
- Worn, bent or seized idler pulleys
- Weak or damaged tension spring
- Loose or damaged spindle pulley
- Bent belt keeper or deck hardware
- Debris packed around pulleys
- Excessive spindle or deck vibration
Confirm the belt
Use the mower model, deck size and OEM belt number whenever possible. Belts that appear similar can have different lengths, widths and profiles.
Check routing
Use the routing decal on the mower or the manufacturer documentation for your exact model. The belt must pass on the correct side of idlers and belt keepers.
Mower Belt Routing Diagrams & Resources
Inspect the spindle system
With the machine safely disabled, check for excessive pulley movement, rough bearings or damage around spindle mounting points. Correct the underlying mechanical problem before installing another belt.
If the deck shakes or becomes noticeably rough only when the blades are engaged, use the Mower Deck Vibration Guide to inspect blades, spindles, pulleys and impact damage before replacing another belt.