1965 Cub Cadet 100

Just bought a Cub Cadet 100 and I'm having a hard time getting the belt for the outer blades to work the tentioner pully won't stay in place how can I fix this also there is no arm on the tentioner should there be one all I have is a bolt that comes up from the bottom of the deck

There is or should be a model identification tag on the top left side, near the outer edge of the mower deck.

If you/we can identify the mower deck model, we can use the parts manual to identify necessary pieces.

No ID tag, photos.

It’s most likely a 42” deck. I don’t think it’s a 38” deck. There should be a spring loaded lever and a pulley that tensions the belt. You could have a broken spring. Or the whole setup is missing.

https://www.ccspecialties.org/implementparts_2.html

Go down till you see the idler springs there are two different ones.

This spring is held inplace by a shoulder bolt. Some had sleeves, one fix is to use a bolt with flat washers stacked up so the spring fits over the washers. Stack the washers so when the bolt is tight the spring and lever can still move.