Outdoor Power Equipment and Small Engines - murray drive belt problems

greeting from newbe:eek: . murray model# 4005002x8A 12.5 b&s. i have replaced the drive belt #37x87ma and drive pulley, but the belt keeps coming off. ihave the mower belly off and was under the unit watching the belt. i noticed that the drive pulley moves up and down on the trans axle shaft when changing gears and reving motor is this normal? :confused: also the belt guides are in place and the belt is on correct. the idler pulley is on and working. when in neutral the belt has a lot of slack it flops around hitting the underbody. please help my grass is goin wild.:wall:

Look closely at the frame near where the trans is bolted on,
Murray had a serious problem in this area in it's latter years.

The frame is l8ikely cracked and broken.

checked mount and frame all ok. i can watch the pulley travel up and down on the shaft. the woodruff key is in place. you can pull up on pulley with your hands.thanks fisher

:confused: o yeah the E clip is also in place..:thinker:

It's normal if it's a small amount. How much movement is it? Is it the pulley moving on the shaft, or the shaft moving in the tranny? Both?

hey guys i took the drive pulley off and noticed on the shaft there are two places for e-clips to go. so i put a clip below pulley and put the pulley on with the key then put on the upper clip and everything lines up perfect. ive ran it for several hours since and no belt problems. the book only shows 1 clip that goes on top of pulley? hope this helps some else. thanks for all ya"lls help. p.s. cheese the slack is no longer a problem thanks............

Good to hear. Just so you know, I believe there should be a thrust washer between that clip and the top of the transaxle housing. That way the clip doesn't wear into the top of the housing or wear the clip thin and cause it to come off. That may be why the clip was gone in the first place.

what part # would it be? i cant find any on the parts list.does it act like a shim?or can i fabracate a piece of pipe.to go over shaft? will it rub the bottom of the trans? thanks cheese

Just use a thin flat washer that fits over the shaft snugly. It's probably not very important anyway, since the shaft pressure is upward, not downward, when the unit is in use. I wasn't thinking of that when I mentioned it before. The thrust washer(s) is on the same shaft but inside of the case, not the top.