My Sears 917.272911 Lawn Tractor is eating mower drive belts. The belt is being worn out in minutes on the flat idler pulley side. When I put the old belt back everything seems to work fine. The new belts that are sold at Sears for this mower appear to be made of a different material.

Safety and Preparation Serious injury can occur if the engine or mower blades accidentally start while you are working with lawn tractors. To prevent this, drive the Murray lawn tractor onto a flat work surface and disengage the mowing deck cutting blades. Engage the parking brake to keep the mower from moving; chock the wheels with a wooden block or brick. Adjust the mowing deck to the lowest position. Turn off the engine and remove the key from the ignition. While not necessary, you may even wish to disconnect the spark plug wire from the spark plug. Mowing Deck Removal You must remove the mowing deck on a Murray lawn tractor to gain access to the belts. Remove the adjustment rod hairpins, followed by the adjustment rod pins from the front left and right sides of the mowing deck. At the rear on the left and right sides, pull out the retaining hairpins and slide the mowing deck suspension links from the adjuster plates to separate the rear mowing deck from the frame. Remove the blade control rod stud, including the hairpin and washer, from the top of the blade control lever shift linkage at the left rear of the deck. Remove the front hanger rod, including the hairpin and flat washer that hold the rod in place. Loosen the belt guide retaining bolts with a socket wrench and remove the engine stack pulley belt so you can slide the mower deck out from under the tractor Transmission Drive Belt Installation Slide the new transmission drive belt between the engine stack pulley belt guides, over the belt guide plate and under the engine stack pulley. Fit the transmission drive belt around the top engine stack pulley. Push the free end of the transmission drive belt up through the transmission shifter hole in the lawn tractor floorboard. Slip the transmission drive belt loop over the transmission shifter. Pull the transmission drive belt down through the transmission shifter hole. Fit the transmission drive belt around the transmission drive pulley and tighten the transmission drive pulley belt guide retaining bolts to hold it in place. Fit the transmission drive belt flat side around the idler pulley. Slide the idler pulley onto the idler pulley stud while holding the belt in place. Tighten the transmission idler pulley retaining nut with a socket wrench to secure the idler pulley to the idler pulley stud. Mowing Deck Drive Belt Installation Pull back on the right side mowing deck mandrel pulley spring-tensioned belt retainer. Guide the new mowing deck drive belt around the right side mandrel pulley and release the belt retainer. Pull the drive belt spring-tensioned retainer away from the mowing deck idler pulley, guiding the deck drive belt around the idler pulley. Fit the mowing deck drive belt around the left side mandrel pulley and under the rear mowing deck cross link rod between the right and left side mandrel pulley. Slide the mowing deck under the right side lawn tractor frame, reconnecting the deck to the frame in reverse order of removal. Engage and disengage the mower deck while driving the mower to test the belt for proper operation.

It sounds like there is a piece missing from the drive belt. The drive belt would be the upper belt on the drive pulley at the bottom of the engine. Another thing it could be is a bad bearing in an idler pulley.

lift the front of the tractor up at least 3 feet and lower the mow deck to give you clearance. push the clutch pedal and lock it down to release belt tension. remove the mower belt from the engine pulley only. remove the trans belt from the idlers about midway back then from the trans pulley & finally from the engine pulley. put the new belt around the engine shaft above the mower drive pulley but not on the drive pulley then around the trans pulley. now you can put it on the drive pulley and finally on the idlers. make sure you have it under all the various keepers or the belt will shred in like 10 minutes. release the clutch pedal & check the belt again to ensure it is in the correct place. replace the mower drive belt & ensure that didn't come off other pulleys in the process. lower the front of the tractor and test

Often there is a keeper on the back of the pulley, and the belt must go inside the keeper. Get an inspection mirror up in there to look if necessary. Start by putting the belt on the transaxle pulley, then on the PTO pulley, then on the idler, last have someone sit on the mower and depress the clutch pedal while you put the belt over that pulley.

How to replace the drive belt on a Toro LX466 Lawn Tractor

1. Jack up the front of the mower-place a couple of blocks under the front wheels (retaining wall blocks from your flower bed work great). Block the back wheels so the mower won't roll off the front blocks.

1. Remove the battery and battery compartment from under the seat. You can now see the cooling fan blade under the seat. The belt runs from the pulley directly under the fan to the front of the tractor.
   

2. Lower the mower deck to its lowest position. Remove the deck hanger rod from the slots in the front of the mower deck.
   

3. Remove the metal rod guard below the engine pulley. It's held in place on one side with a bolt, and the other side with a cotter pin.
   

4. Take a large pair of channel lock pliers (about 18 in long work great) and clamp them down directly on the engine pulley, but not so tightly you distort the pulley.
   

5. Remove the bolt from the pulley. It's a right-handed bolt, so turn it counter-clockwise to remove.
   

6. Slide the pulley down the shaft until you can work the belt off. If the belt is too tight, then remove the spring from the idler pulley under the tractor. It's hooked on a bolt near the side of the tractor. You can remove it by grabbing the end of the spring with a pair of needle-nose vise-grips and slipping the end off the bolt. Then remove the old belt from the tractor.
   

7. Take a new belt (preferably Kevlar) and start at the back of the tractor (with the pulley under the cooling fan) and thread it through to the front of the tractor. The flat side of the belt rests against the idler pulley with the flat sides.
   

8. Work the belt over the engine pulley and slide it back on the shaft. Tighten the bolt on the engine pulley hand tight. Then check the belt to make sure it hasn't slipped out of the groove on the cooling fan pulley.
   

9. Clamp the engine pulley with the channel lock pliers and tighten the bolt.
   

10. Make sure the belt is routed correctly on the idler pulleys. If you had to remove the spring on the idler pulley, replace it. You can do this by grabbing it with the needle-nose vise-grips and placing it on the bolt-make sure it's above the washer. Then remove the vise-grips and gently pry it over with a small screwdriver until it slips into place.
    

11. Replace the metal guard below the engine pulley. Hook the mower deck back onto the deck hanger. Replace the battery compartment and battery. Unblock the mower.
    

This is for a Scotts 1642. Picture yourself sitting on the mower looking down at the deck. Starting at the tractor pulley, the belt runs from the right side of this pulley to the left side of the tension arm pulley, around this pulley to the left side of the right hand side mower blade pulley, around this pulley, across the deck to the smaller left hand side idler pulley, then up to the left hand side mower blade pulley, around this pulley to the second (larger) idler pulley, around this pulley and back to the left side of the tractor pulley. If you make a small sketch of the deck pulley arrangement it will be easier. Keep in mind some of the pulleys are for the "V" side of the belt and some (The tension arm pulley & larger idler pulley) are for the flat side of the belt. Be sure the belt is not twisted and lays in a continuous circle with the "V" side of the belt on the inside before you start.

from http://www.ssbtractor.com/wwwboard/view_all.cgi?bd=lawn&msg=135

Please vote !!

First things first! Before you installed the new belt, did you check the blades and idler pulleys to see if they all turned freely with no resistance while the belt was off and the blade brakes released? Release the blade brakes by engaging the handle with the engine off!
When you installed the new belt, did you put the back side of the belt against the flat pulleys and the inside of the belt in the V-pulleys? Did you double check to make sure you didn't inadvertently miss a belt guide getting the belt on the outside of it instead of underneath it. Did you look at the picture in your owners manual to make sure you had it routed correctly and make sure it is not rubbing against anything when you have the blade lever engaged? CHECK THIS WITH THE ENGINE OFF If you don't have your owners manual, look under the foot boards on the tractor, many of the Sears tractors have the routing diagrams there. If it is not there you can go to searspartsdirect.com , enter model number 917.257644 (NOTE the number difference) and look at the picture of the deck, it shows what the belt should look like when it is installed. You can also download an owners manual there. As best as I can remember, there is no adjustment for the idler pulleys.

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

I don't have a diagram but it shouldn't be to hard. You will have to drop the deck. Then when installing the new belt remember to always place the inside of the belt (V) into the pulleys and the outside of the belt (flat side) up against the larger idler pulley. When you have the belt on properly it should be snug. If you have excessive play you need to try a different routing around the idler.

Good luck and let me know if this helps.
Thanks
roundo4

I don't have a deck diagram but you should be able to figure it out it you put the back part of the belt (flat) up against the pulleys that are wide and the narrow part (v) into the smaller pulleys. It might take a couple of times but it is not that hard to figure out. Also put the (flat) side of the belt on any tension idlers. Hope this works.