My Murray Model#42515x92 keeps slinging off the mower belt after 2 or 3 passes !! I checked bearings on the pulleys but didn't find any slack !!

Hello Donald, I would check any idler pulley bearing , tensioner pulley bearing, or mower deck bearings that runs on that belt. You might have a bad bearing causing the belt to burn off. Also check pulley alignment .

Try this site to get your manual and see if the exploded parts diagrams help

check belt that goes from motor to trans. check pulleys and the bearings in the pulleys for same belt.

Could be a number of things included but not limited to.....blade spindle bearings....idle pulley or engager pulley......could also have a bad spot in belt....causing a vibration. This vibration could also lead to deck coming out of level as that model have a leveling adjustment on the deck level control lever.

check the tenson spring may be weak or off

Sounds like one of the pulley bearings on the deck is locked up. TURN OFF THE MOWER! Crawl under there and try to turn each pulley by hand. The pulley(s) that has the blade on the bottom has 2 bearings, the others just have 1 bearing each. Once you figure out which pulley is locked up, google your model number and look for a parts diagram. It will give you the part number for the failed pulley. Pulleys are not very difficult to replace. Basic hand tools and a couple of hours will usually take care of it. The replacement part is available online at many retailers, or try your local mower repair guy for the part. I recommend replacing the belt at this time also, as it has been under alot of stress and may break soon after.
Good luck!

Try taking the belt off of another pulley, put it on the other ones and the tensioner pulley, then start it on the last one and pull the tensioner and get the slack in the belt and roll the pulleys and it will feed the belt on that pulley.

Hi how old is your belt, if it is an original one or even a replacement with use go to your local repair shop and get a new belt --- take your old one so they match it up as well as your make--model---serial number of the mower. this will get you the right belt. you have a pulley that should take up the slack so I would look at the belt for streching and wear.

Get the model number off the tractor, go to:

www.murray.com

enter the model number and you will find a manual with pictures of how to route the belts along with a lot of other good information

You can go to www.murray.com/manuals/ , put in your model number and download the manuals. As for teh brakes, there is a 1/2 inch nut in the center of the brake caliper that you tighten or losen to adjust the brakes. Put your tractor in neutral on a flat surface, tighten the nut just until you can no longer roll the tractor freely, stop as soon as you reach this point then back the nut off 1/2 turn and you should have good brakes again.