Craftsman riding mower blades won't disengage

PamSantana

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Hi everyone,
I recently bought a used Craftsman riding mower. The model number is 917250810. Shortly after I bought it, the blade drive belt snapped. I bought a new one and installed it. Seemed pretty simple. However, now the blades run even when the lever is in the off position. I've gone over it and the cable appears to be working correctly. The pulleys move easily when I engage and disengage the lever. I can't see any reason why the blades are spinning when they're disengaged. It was working fine before I put the new belt on, so I must have done something wrong, but I can't figure it out.
 

keakar

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assuming you confirmed the sporing that releases the belt is there and working properly, it probably needs a different belt size

my guess is they replaced the deck on it with an ayp mower other then craftsman so its got the belt number thats listed on the mower but not for THAT deck

i hope you still have the old belt, measure it on the outside (back part) edge and see what size it is then go on ebay and search for that size stens belt and buy that, then write that number on the mower so you never forget it.

some mowers use two 4" idlers and some use a 4" and a 3" and that uses a 1" different belt size

there is nothing wrong with having the wrong deck on it but the belt used wont match the one listed for that mower
 

PamSantana

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I took the belt with me to the store and they measured it. It measured to be 101" long and 1/2" wide, which corresponds with what the manual calls for. It appears to be the correct size. When you asked if I confirmed that the spring that releases the belt is there and working properly, are you referring to the spring that the cable is attached to? The one that moves the pulleys to tighten and loosen the belt when I move the lever to engage the blades? If so, yes, it seems to be working properly. I have the battery charging right now because I wore it down while I was trying to figure it out. I've taken the mower deck down four times trying to figure it out. I can see the cable moving the pulleys back and forth. It "looks" like the blades should disengage. I can't see any reason why they're not. It's frustrating! Thank you for your advice!
 

Scrubcadet10

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1507146P-00007.png

Sears parts direct list the dimensions at 1/2" wide x 101 3/8" length.
Part number 429636.
 

PamSantana

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@Scrubcadet10 , thank you for your insight! I ordered a specific belt for my mower online and switched it out and now it works properly. The one I bought in the Napa store said 101", but when held up to the one I ordered, it turned out to be almost 2 inches shorter. That was the problem. Thank you again!
 

Scrubcadet10

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Thank you for letting us know it fixed your problem... It will help someone in the future.
Good luck and Happy Mowing ;)
 

Hammermechanicman

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Different belt are neasured differently. Most outdoor power equipment uses FHP fractional horsepower belts with a 3L, 4L or 5L designation. These belt are measured around the outside circumference. Most automotive belts are A, B or C belts. These are measured around the inside circumference. You need to know what type of belt the mfgr used for the OEM belt. The difference is usually about 2 inches.
 
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