Walk behind belt drive question

[burkcs]

I have an Exmark Metro HP (belt drive). The right side belt keeps riding up on the edge of the larger pulley located closest to the wheel. Without to much investigating it appears that the upper pulley is not aligned properly with the lower pulley (just a guess). I have attempted to increase the belt tension on this one side however the belt continues to ride up on the side of the larger pulley. This causes the mower to pull to the right side.

Can you provide me with any ideas on what the cause might be?

[JoeinJasper]

Check the set screw on the drive pulley on the transmission shaft. If the set screw is lose, it will allow the pulley to slide to the side and the belt to ride up. Joe

[WhitakerServices]

I had a similar problem on my Husq. where the belt kept riding off the wheel pulley and eventually chewed up the $50 belt. The fix was to shim the wheel with thin washers. I put about 3 on the problem side and it lined everything right up.

I am sure that this will cause your pulling to the side problem. But another thing that will cause it to pull is uneven tire pressure or even different diameter tires. When I purchased my first wb. a scag 36 it was pulling to one side horribly the mower shop kept telling me that one tire must be underinflated. I knew that they weren't. after about 2 weeks I could not stand it any more my right hand was killing me from trying to keep the mower tracking straight. I checked the diameter of the tires (at proper pressure) and one tire was 1 inch larger diameter than the other. problem solved. this was on a brand new mower.
good luck