Blade Speed
 

I have a Cub 2518, with a 48" deck that I have had for about 15 years. I am now having trouble with the speed of the blades. It does not throw the clippings like it use to, and leaves some grass uncut. I can hear the blades seeming to speed up and slow down. It just started doing this. The blades were replaced last season. I noticed the problem on my first cut of this season, so I sharpened the blades, and greased everything. I did notice 2 of the idler pulleys a little noisy so I replaced them, and both belts. Still no change. Any ideas? The PTO was replaced about 4 years ago. I am stumped. The blades seem to spin freely. Do you think it could be blade shafts? They are original.

Sounds to me like a loose belt, or at the very least, a slipping belt. Better make sure the new ones you bought are the right ones.

Unless you didn’t tighten the blade after removing them, the spindles have nothing to do with it.

You did put the blades on correctly and not upside down, right?

I've never had one of these "newer" decks but on the old ones the idler is spring loaded to keep tension on the belt. If the idler bracket rusts to the bolt it's supposed to pivot on they will get stuck in place and let the belt slip. Take it apart, clean it up good and grease the pivot when putting it back together.

yeah, the blades are on correctly. The belts are bought directly from cub. Do you think it could be the PTO clutch not totally locking down?

Well.... I'm still sure something is slipping. Look it over better. Check to see if the pulleys are wore out. Maybe the belt is bottoming out in the pulley. It's not difficult to find an issue like this. Usually you can find it with your eyes.

Any time I've had a tractor do what you describe it's been something slipping that causes it.