MTD Yard Machine drive belt issues


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Old 04-13-22, 08:28 PM
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MTD Yard Machine drive belt issues

I own a 2000 Yard Machine with 42” deck. The lower drive belt was old and rotting away (probably the original). I swapped it out with a new belt, oem from MTD, and I know it to be the correct belt. My issue is that the new belt has a lot more slack than the old belt. After buttoning it all up I gave it a test drive and the belt would only
engage if I floored it. I then looked up in the manual and followed what it said for adjusting the tension. I adjusted the tensioner to have the least amount of slack as possible but the belt is still just as loose. Do any of you have any thoughts? I replaced the crankshaft pulley as well as the two idler pulleys. I also replaced the needle bearings in the variable speed pulley. Im honestly at a loss as I can’t find any other areas to adjust for this.

https://apps.mtdproducts.com/manuals/770-10131b.pdf
 
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Old 04-14-22, 12:23 AM
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Every belt and even pully manufacture makes their parts to slightly different dimensional sizes and that can add up to the way the parts engage each other.

I have a 48" walk behind mower with 3 belts and the main drive belt was a PITA getting it to fit.

I ended up getting several belts, all +/- 1" and trying them until I got the right one.
 
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Old 04-14-22, 05:40 AM
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Is there a way to verify variable speed pulley is fully expanding at speed? Can you compare ID of old and new belt?
 
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Old 04-14-22, 08:08 AM
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Can you compare ID of old and new belt?
You can but you stated that pulleys were changed so that may be a factor!
 
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Old 04-14-22, 01:42 PM
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I’ll have to dig the old belt out of the garbage when I get home. The new belt is 5/8” and 90.8” long. The engine pulley I replaced would be the only pulley with the v-grove that interfaces with the belt. I’m wondering if that might be the issue as it doesn’t engage unless it has max tension on the belt. I think the variable speed pulley is working correctly by what I can tell. I may order the OEM MTD pulley and see if that helps at all.
 
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Old 04-15-22, 09:36 AM
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I forgot to mention that I ordered a new engine pulley that is OEM from MTD. I’ll let you know if this remedies the issues.
 
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Old 04-18-22, 09:29 PM
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I installed the new pulley today and that was the issue. I put the off brand next to the OEM and the off brand ever so slightly seemed to have a tighter angle in the V channel. The new one engages the belt correctly and now has full range of speed. Thanks for the help!
 
 

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