Owners of older Murray riding mowers can perform repairs with replacement parts purchased from home improvement stores, local small engine shops or on the Web. Most Murray manuals can be downloaded free from the manufacturer's website or from websites that specialise in manuals. Many Murray mowers were sold under the Craftsman brand, so the manual may be available from Sears. These mowers have two belts: the motion drive belt, which sends power from the motor to a large (stack) pulley, and the mower drive belt, which transfers power to the centre blade pulley. Replacing either belt requires only ordinary tools and usually takes less than an hour.
Stop the blade by moving the attachment (blade) clutch handle to the disengage position, pointing towards the back of the mower. Sit on the seat and pull the deck lift lever in towards your legs then lower the deck to the middle position. Locate the blade drive linkage assembly on top of the mower deck on the opposite side of the deck from the grass discharge opening. The linkage connects the clutch assembly to the pivot rod and bracket assembly (attached to the mower deck) by a clevis, a U-shaped fastener secured by a pin through holes in the ends of the two arms. Pull the cottar key (half-round metal hair pin with one leg bent into shallow arches) out of the clevis pin and remove the clevis pin. This disconnects the clevis from the pivot rod and bracket assembly.
Locate the level adjuster assembly on each side of the mower deck. The level adjuster plate is a circular, scalloped plate with holes. Each plate is attached with a pin through one of the holes to a hanger, a triangular bracket attached to the deck housing. Remove left and right level adjuster pins from the hanger on each side and move the whole mower housing slightly to the left for the right side or right for the left side until the hanger pin clears the hole on each adjuster plate. Remove the long pin from the front deck hanger.
Remove the mower drive belt from the motion belt stack pulley, which is the large metal pulley above and slightly to the side of the centre (mandrel) blade pulley. Remove the mower housing by either sliding the mower deck out from under the mower or by lifting the front of the mower and rolling it backwards away from the mower deck.
Push the clutch/brake pedal forward to lock the parking brake. Loosen the belt guides at the motion belt stack pulley. Pull the motion drive belt off of the idler pulley, which is the small pulley closest to the centre blade drive (mandrel) pulley.
Install the new motion drive belt by sliding it between the stack pulley and the belt guide, and the belt retainer and idler pulley. Position the belt around the motion drive pulley, which is the pulley closest to the left rear tire (facing the back of the mower.)
Check the belt to be sure that the "V" side is inside the pulleys and that the belt is inside all the guides. Check the belt guides to be sure they are all tight and that nothing is rubbing on the belt.. Check the clutch/parking brake to make sure it is engaging the belt properly. Reinstall the mower housing and check that all pins, bolts and springs are in their proper place.
Engage the clutch/parking brake. Disengage the attachment (blade) clutch. Lower the mower deck to its lowest position. Detach the attachment (blade) clutch clevis from the pivot rod and bracket assembly.
Move the belt retainer away from the idler pulley. Slide the old mower drive belt off of the pulleys and away from the belt guides. Cut the belt with metal shears for easier removal.
Pull the belt guide away from the blade drive (mandrel) pulley. Position the new belt on the pulley mandrel pulley with the belt's "V" side against the pulley groove. Pull the belt retainer away from the idler pulley and position the belt in the idler pulley. Pull the belt into position between the stack pulley and the belt guide.
Check the belt for tension. The belt will be slack when not engaged. If it slips out of position inside the belt guides and pulleys, adjust the attachment (blade) clutch by detaching the clevis from the pivot rod and bracket assembly and manually turning the clevis to decrease the length of the clutch rod. Reattach the clutch assembly and the mower is ready.
Clean the deck housing of grass and debris, and inspect the condition of the blade while the mower housing is off.
Turn off the ignition, remove the key and put it in your pocket before beginning work. Detach the spark plug wire from the spark plug to further guard against accidentally starting the motor.