[dkarten78]

This Craftsman has an issue with the mower deck blade belt. I have a new belt installed & it is too loose, blades do not get up to speed, same as the old worn belt. I have the belt routed correctly and all pulleys seem fine, I tried adjusting the front support so the deck is further back which gives better tension but now the deck is not level & I have to cut in position 4 or 5, it's like it's the wrong belt for this 46"Deck, any suggestions?

 

[JP Savage]

Probably sold you a belt that was to the next inch measurement. So too big.
Use the Craftsman P/N and find one the exact size. Usually Craftsman belts in general are Inches and a fraction of an inch. Like 89-3/8" 89 is too small, 90 is too big.
Not saying that is the size you need, just an example.

 

[dkarten78]

I ordered the belt by the part #.The belt I ordered is the same size as the old belt, the mower was doing exactly the same thing with the old belt. I ordered another belt, by the part #, from a different vendor, it’s the same size

 

[dave_r]

You mentioned the belt is routed correctly (you've verified this from the manual or some diagram of how it should go?), so next up is looking at the tensioner pulley, that it can move freely parallel to the belt path, can't move much in the other direction, and that the spring provides good tension (depending on the setup, this may be adjustable).

 

[dkarten78]

You mentioned the belt is routed correctly (you've verified this from the manual or some diagram of how it should go?), so next up is looking at the tensioner pulley, that it can move freely parallel to the belt path, can't move much in the other direction, and that the spring provides good tension (depending on the setup, this may be adjustable).

Tensioner pulley moves freely and seems to be fully engaged when lever is moved into position

 

[Alien5044]

Deck hangers worn allowing belt to be too loose?
Is belt wide enough to prevent the belt from bottoming out in the V groove of the pulleys?
Dave_r mentioned the spring tension, it should be pretty firm so the belt does not deflect much.

If the tensioner arm, when engaging the deck, is all the way at its maximum position, then the belt is just too long. It should have some remaining travel when the belt is tight and running the deck.

 

[Dave Wells]

Most common issue is a seized blade pulley brake.