My riding lawn mower loses speed when under stress(hills). Also, strange noise coming from the front, I think.

there should be two drive belts. they should be replaced both at the same time. if one is wore so is the other one. use the correct belt, from a lawn mower parts store.

Try spraying the belt with a belt dressing aerosol. You can get this at an autozone or other parts house. New belts sometime's take a little time to wear into the groves an old belt creates.

lift the front of the tractor up at least 3 feet and lower the mow deck to give you clearance. push the clutch pedal and lock it down to release belt tension. remove the mower belt from the engine pulley only. remove the trans belt from the idlers about midway back then from the trans pulley & finally from the engine pulley. put the new belt around the engine shaft above the mower drive pulley but not on the drive pulley then around the trans pulley. now you can put it on the drive pulley and finally on the idlers. make sure you have it under all the various keepers or the belt will shred in like 10 minutes. release the clutch pedal & check the belt again to ensure it is in the correct place. replace the mower drive belt & ensure that didn't come off other pulleys in the process. lower the front of the tractor and test

sounds like a belt to me not tight enough against the pullys

kubota does & i also think john deere does try them

Your drive belt is worn/slipping

Either the belt routing is incorrect or there is a tensioner which needs adjusting. Recheck your belt installation. Oh, it could be the wrong belt, too.

Similar thing happened to me and it seemed to be nothing more than a completely clogged air filter. When replaced it was fine.

Maintaining Riding Mowers Regular maintenance can reduce repairs.

Components of a typical riding lawn mower. (click to enlarge)

It's fun to ride around the yard on the mower, watching scrubby grass (and weeds) turn into trimmed lawn. However, when the grass looks as bad after you mow as it did before, or the mower doesn't want to start, riding mowers aren't as much fun. That's when it's time to put on your Fix-It Club hat and have some more fun.

A riding lawn mower is a gas-powered machine for cutting grass. The engine turns a rotating blade that cuts the top off the grass blades to a specified height. The operator sits atop the mower on a tractor-type seat with speed and height controls nearby. Riding mowers also can be used to pull small utility carts for other yard jobs.

To remove the mower deck:

1. Make sure that the parking brake is locked.
2. Place scrap lumber under the front and rear of the deck.
3. Use the deck lever to lower the deck.
4. Remove attachments from the deck.
5. Remove the blade drive belt from the front pulley.
6. Remove the front and rear deck fasteners, following instructions in your owner's manual.
7. Use the deck lever to raise the deck.
8. Remove the scrap lumber.
9. Remove the deck from under the mower.

To adjust the drive belt:

1. Remove the belt from the large idler pulley.
2. Remove the belt from the adjustable idler pulley.
3. Carefully remove the spring-loaded large idler pulley.
4. Loosen the adjustable idler pulley and move it slightly toward the rear of the mower to tighten it[md]or move it toward the front to loosen it—and retighten the pulley.
5. Replace the belt.
6. Check belt tension and readjust as needed.

give as the model so we can help.