Have a murry 46 older one.. for some reason it started to chew up the belt from engine to blades.. I have replaced the idler pulley and belt.. but when I start to cut (deep grass growing along with this problem).I can cut perhaps.. 200 feet and then the belt rides UNDER the idler pulley and gets stuck there between pulley and spring end.. New part is correct, belt is 37X70 correct for model.. Just started doing this.. ran perfect for long time. Had a plastic idler before... and it chewed it up.. go replacement which is B&S part now.. First time I ran new belt it ran for short time and got under pulley.. ANY ideas?
It is if when it loads or warms up the belt decides to go under pulley.. as if the idle pulley is to high. But how can that be?
RSVP Need Help as grass obscures dog when he goes out.. and he is big hound.:confused:

Have a murry 46 older one.. for some reason it started to chew up the belt from engine to blades..I have replaced the idler pulley and belt.. but when I start to cut (deep grass growing along with this problem).I can cut perhaps..200 feet and then the belt rides UNDER the idler pulley and gets stuck there between pulley and spring end.. New part is correct, belt is 37X70 correct for model.. Just started doing this.. ran perfect for long time. had a plastic idler before...and it chewed it up.. go replacement which is B&S part now.. First time I ran new belt it ran for short time and got under pulley.. ANY ideas?
It is if when it loads or warms up the belt decides to go under pulley.. as if the idle pulley is to high. but how can that be?
RSVP Need Help as grass obscures dog when he goes out..and he is big hound.:confused:

NOTE I pulled belt for umteenth time.. it is the LOWER portion of belt that is showing wear along edge at bottom. These things are $32.88 with tax... so getting expensive to "fix" which is not a fix.. ANY IDEAS REALLY NEEDED.. something is out of whack. HOW CRITICAL IS the mover height from side to side being equal? NOTE the thing ran great last year.. when it was parked for winter.. now this. As it chewed up the plastic idler wheel at engine to deck belt... parts book from B&S (now owns murrary) shows a metal idler pulley.. but belt slides off at bottom and gets caught between pully and spring end.. again at about $33 a pop... belts get expensive.. using 37X70 belt which seems to fit fine.. SO?? :eek:

Tearing up one edge does seem to be on the surface, an alignment issue, but before you do that go to DAYCO.COM - MARKIV Automotive Aftermarket (http://www.dayco.com) and locate the Dayco part number for your Murray. Then go to a NAPA auto store and get the belt using the Dayco #.

Tearing up one edge does seem to be on the surface, an alignment issue, but before you do that go to DAYCO.COM - MARKIV Automotive Aftermarket (http://www.dayco.com) and locate the Dayco part number for your Murray. Then go to a NAPA auto store and get the belt using the Dayco #.


What will getting the belt do from me. I have a new in there now, it is showing some wear and headed for same fate as last one.. really odd as all ran fine last year.. wondering if very long and thick grass doing it, putting strain on belts.. overloads..

There are a lot of issues that can happen when non OEM belts are used. Just want to make sure you have the right belt and not one that has been "matched up".

I know personally what happens when you put the wrong belt on a rototiller.

What will getting the belt do from me. I have a new in there now, it is showing some wear and headed for same fate as last one.. really odd as all ran fine last year.. wondering if very long and thick grass doing it, putting strain on belts..overloads..


Checked you site but only PN I have is murry 37X70 which does not cross ref to theirs.. when I think about it, I believe that two years ago I got a belt from NAPA much cheaper and guy there sold me a 69 inch as said issue was probably the 70 was not the right one.. not sure... but you reminded me a bit. And wife agreed.. never argue with her.. can you find a 69 PN for NAPA... good store not far from here. Seems I cannot get that site to do it's thing.. price would help.. but pretty sure the 69 was about half of what Murray parts guy sell for.. THANKs.

I get a Dayco L477 using that part number. NAPA will cross that to a Gates belt, I think.

I'm getting some conflicting results.

Can you find the full model number for the murray. I think 46 is too short.

I want to try to look things up by application.

I cannot find the model nr as the tags removed.. both tractor and deck.. but used a 37x70... according to part book by B&S I found on www...but there is also a 37X69 which I think I ended up using two years back. But the odd thing still is it chewed up belts.. along edge as it rode off and under the idle pulley.. the one that feeds right off engine to left blade and center blade and also dries belt for left blade.. I found a NAPA sub for the 37X69.. the belt using now is 37X70 and is marked Murray 37X70.. but it not working right.. as said it rides under the idle pulley.. ran it on concrete it seemed OK.. but when on grass.. kind of long as am working on the beast and grass grows more each hour,. but after short run on grass.. it comes off the idler and goes under it.. and it seems somewhere it is getting wear on edge.. what used ot be triangle belt is ending up rounded.. NAPA Part nr is sme 707860 for the 69 and same price as the murray.. the 70 is $8 cheaper..

Still cannot find why the thing is doing it.. as was put away for winter.. when I started it up it took out the plastic idler as it had rode under it.. same as the metal one B&S uses as replacement.. then belt went with same wearing.. belt almost twists in some places.. around idler and blade pully.. why this is going on I do not have a clue.. and it is leveled within 1/3 inch l to r.. When I watch it run, blades turn fine. And belt seems level.. but in grass?? Maybe 50-100 feet and goes under idler..

1/3 of an inch is way too much out of alignment. Try to get them to line up within 1/16".

You didn't hit anything that would bend any of the shafts, did you?

1/3 on the adjustments on older murry is close.. as very limited.. all shafts are straight and run fine.. was running fine when it got put away... that is disturbing part of it all. And was cutting in back field with no issues.. I wonder what the impact of 69 inch belt verse 70 might be.. but when running blades over concrete. Not loaded from grass.. all seems to be running true.. wonder if the 1 inch in belt could be the issues?? Really tough to work on without model nrs.. have to "look-see" to find matching parts..

Did you check the shafts for end play?

Most everything tight, no play issues... had to tighten mount on idler pulley but no impacts.. seems that when loaded it will act up. Which is odd as cut much deeper stuff when I made a few more or less bug free paths in back fields...

Sorry, kiss, I'll let you handle this one, seems it is long and drawn out, and if someone doesn't listen, and try things, like the 1/16" tolerance. I must move on.

sorry, kiss, i'll let you handle this one, seems it is long and drawn out, and if someone doesn't listen, and try things, like the 1/16" tolerance. I must move on.


Since you do not know of what you say. PLEASE DESCRIBE IN DETAIL HOW ONE sets the 46 inch to within 1/1/6th.. as you are dreaming.. it cannot be done, but would be interested in your fable on how to do so.. or perhaps you best "Move on"..

THERE ARE NO ADJUSTMENTS TO PULL THAT DECK TO WITHIN 1/16th. NONE... PN is 403334 so look it up and describe what cannot be done.. or admit lack of product knowledge as you are 100% incorrect and hope your advise is better for other lines.. but suspect as to accuracy after you cheap shot..

Did you check the shafts for end play?

UNIT NOW works OK.. removed all I could from deck, pulley's, blades, idler arms etc.. Reassembled ALL and fired up.. works like it did last year. Not a clue as to what was wrong. One for those things that often happens.. probably something was loose and did not show up when checks run.. and when R&R(Reinstall) all lined up.. A mystery to me... but those older units sometime go out of whack, dirt in somewhere etc.. according to friend whom has 42 inch.. so will see how it goes.. thanks for ideas.. but the older ones back to 1992 or so vintage were built loose so hard to get really good measurements.. sort of like rework on old Ford gearbox of a 36 I have. Was told that only way to stop it from slamming out of second gear (floor shift that would fly back.. knee breaker if in way) when backing off gas... was to get gear set that meshed up perfectly.. did that.and OK for four months.. then got loose and back to old tricks... I now live with it.. Again thanks.. but these things have mind of own. So it seems.

Very strange.

Perhaps just that old eng bug of build up of tolerances as things loosened up.. each one checked OK.. but in total.. Not exaclty a new item when discussing HW failures, and Murray had a lot of loose tolerances it seems, even when new.