mtd yard man 46 in ride mower, 13ao772h755, replaced all belts now everything works but speed lever has no effect..clutch is pulling the variable pulley forward and when released ti returns to original position which looks correct, I have searched for a step by step adjustment but haven't been able to find one..the new small drive belt that drives the trans appears to be a bit wider than the original but fits nicely in all of the 3 pulleys but the variable pulley will not slide up or down..ANY help will be greatly appreciated
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Export threadSeniorCitizen
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mtd yard man 46 in ride mower, 13ao772h755, replaced all belts now everything works but speed lever has no effect..clutch is pulling the variable pulley forward and when released ti returns to original position which looks correct, I have searched for a step by step adjustment but haven't been able to find one..the new small drive belt that drives the trans appears to be a bit wider than the original but fits nicely in all of the 3 pulleys but the variable pulley will not slide up or down..ANY help will be greatly appreciated
If the variable slides free without any belts installed, and the springs are attached in the original factory locations that pretty much leaves the belts not being OEM specifications as the culprit.
I repaired one of these for a neighbor bout 20years ago and bought OEM belts at Lowe's. Since then I've read the OEM belts are mandatory for one of these variable speed systems to operate correctly.
Note: I did gather info. that the owner had never read the operators manual and used the clutch exclusively when changing speeds. This is not how that system was designed to operate.
bertsmobile1
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mtd yard man 46 in ride mower, 13ao772h755, replaced all belts now everything works but speed lever has no effect..clutch is pulling the variable pulley forward and when released ti returns to original position which looks correct, I have searched for a step by step adjustment but haven't been able to find one..the new small drive belt that drives the trans appears to be a bit wider than the original but fits nicely in all of the 3 pulleys but the variable pulley will not slide up or down..ANY help will be greatly appreciated
:welcome:
Vari Drives are very sensitive to the belts being used.
SO it is either genuine MTD belts or OEM Spec belts from Stens, Oregon, Rotary or Prime Line.
Ignore all the much cheaper usually unbranded belts you see online sold as "replacing" or "fits" actually go in the space, but won't work.
The system works by the upper ( short belt ) forcing the sliding pulley down fully which is done by the spring.
To make the mower go, your foot has to apply more force on the lower belt that the spring does to the upper belt.
If your mower has a "Speed Selector", all that does is limit the travel of the foot pedal.
If the front belt is too long the system will not work because you can not get enough tension in the belt to force the sliding pulley to move up.
If you have hooked the tension spring on the small belt in the wrong place the pulley may also no move.
It is a very fine balance.
A bad bearing in the tension pulley or excessive wear on the tension pulley arm ( either or both of them ) will also cause the mower to be "stuck in first "
thanks to all for the quick replies. I started this project when the deck belt quit turning the blades, all of a sudden with no warning..the belt had stretched about 2 inches but i never noticed it slipping or squealing..
I was ignorantly unaware that there is a tag under the hood that lists the correct belts to use, but I set out online to find the correct belts using the only diagram I could find which was a Jack's small engine site with an exploded view of the parts and connections, and is virtually impossible to comprehend, but does have supposedly the correct belt numbers, however I find that the transmission drive belt listed on the diagram for my machine is different than the sticker under the hood. Live and learn. the variable pully will not slip up and down with the belt in place but will with the belt removed..I ordered these belts from Walmart, where I bought the machine, and they are advertised to be exact replacement for OEM parts..they are from a company "Genuine Parts", and Walmart got them to me in 2 days, so that's why I used them but will know better next time. The belt that I received seems to be a tiny bit wider than the original, so I am assuming that this may be the problem.
Once again, thanks for the quick replies, and also the primer on variable speed machines. This is quite a difference in technology from the manual mower that I was introduced to when I was 8, and I have a new respect, but am very disappointed in my own stupidity. Will now contact MTD for the correct belt.
I was ignorantly unaware that there is a tag under the hood that lists the correct belts to use, but I set out online to find the correct belts using the only diagram I could find which was a Jack's small engine site with an exploded view of the parts and connections, and is virtually impossible to comprehend, but does have supposedly the correct belt numbers, however I find that the transmission drive belt listed on the diagram for my machine is different than the sticker under the hood. Live and learn. the variable pully will not slip up and down with the belt in place but will with the belt removed..I ordered these belts from Walmart, where I bought the machine, and they are advertised to be exact replacement for OEM parts..they are from a company "Genuine Parts", and Walmart got them to me in 2 days, so that's why I used them but will know better next time. The belt that I received seems to be a tiny bit wider than the original, so I am assuming that this may be the problem.
Once again, thanks for the quick replies, and also the primer on variable speed machines. This is quite a difference in technology from the manual mower that I was introduced to when I was 8, and I have a new respect, but am very disappointed in my own stupidity. Will now contact MTD for the correct belt.
SeniorCitizen
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Was this lawn tractor moving at all before you replaced the belts? Something seems a little strange.
bertsmobile1
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From the top.
Kevlar fibre mower belts do not stretch ( well not much any way )
They get thinner because they wear away on the sides where they are in contact with the pulleys.
As the belt get thinner, it sits deeper in the pulley so it gets slack.
Thus a new belt will usually be wider than the old belt, because belts wear on the sides.
The belts for vari drive systems are shallower than a std belt of the same width.
This is to prevent the belt bottoming out on the pulley shaft.
When this happens the belt slips and does not drive the pulley.
Triple check the routing of the lower ( long) belt.
You can install it in several wrong ways and when done wrong, the tensioning arm can not put enough tension on the belt to force the sliding element to go up.
Not also the pulley can not slide unless it is turning.
Kevlar fibre mower belts do not stretch ( well not much any way )
They get thinner because they wear away on the sides where they are in contact with the pulleys.
As the belt get thinner, it sits deeper in the pulley so it gets slack.
Thus a new belt will usually be wider than the old belt, because belts wear on the sides.
The belts for vari drive systems are shallower than a std belt of the same width.
This is to prevent the belt bottoming out on the pulley shaft.
When this happens the belt slips and does not drive the pulley.
Triple check the routing of the lower ( long) belt.
You can install it in several wrong ways and when done wrong, the tensioning arm can not put enough tension on the belt to force the sliding element to go up.
Not also the pulley can not slide unless it is turning.
Was this lawn tractor moving at all before you replaced the belts? Something seems a little strange.
yes, was moving fine in forward or reverse, and 7 position speed lever worked as it should and mower had plenty of speed. None of the belts had broken, although the deck belt had stretched and wouldn't turn the blades..the new belt that I ordered is a Genuine Parts brand, and the MTD customer service person said it is a satisfactory replacement. I am going to put the old belt back on today and see what happens. I think I've got everything back as it is supposed to be, the mower belt from the pto as well as the deck belt all work good. Does anyone know if there is a shop manual for this machine, the MTD person wasn't any help with that. I am still a little fuzzy with this variable speed technology, so my success is dependent on trial and error, and a factory shop manual would be a great start.