Why does the belt on my mower deck keep breaking?

Any debris on top of the deck e.g. thumb sized mulch, driveway stones, pencil diameter sticks or larger. All may cut and snap a belt if they get wedged between the belt and any of the pulleys.

Any hard foreign object of the size that will jamb into a pulley v groove.

if not level or not proper adjusted it will or pulley -bearing or tensioner problem -bent blades

Turn off the mower completely and clean out beneath the deck with a mower-cleaning tool to remove any built-up grass deposits. As debris collects inside the deck, the blades can't move freely and you'll have unusual patterns or unevenness forming in your lawn as a result. The mower-cleaning tool scrapes this debris off and restores the deck to proper function.
Measure the height of the mower deck with a ruler when the mower is on flat ground. The deck should be an equal distance from the ground on all sides to ensure an even grass cut. Adjust the leveling bolts on both sides of the deck as needed to readjust the height until it's even. If the mower hits something like a rock or a large stick while mowing, it may knock the deck off balance.
Inspect the deck for any dents or warping. Use a rubber mallet to carefully straighten any dents in the deck if the deck is metal. Plastic decks generally need replacement if they crack or warp.
Remove the deck for a more thorough inspection or cleaning as needed. Remove the grass catcher and take off the pins or mounting bolts holding the deck in place. Lower it to the ground and pull it out from under the mower. Unhook the cutting blade from the underside of the deck with a wrench and set it aside.
Sand off any rust with sandpaper and use the mallet or a hammer to eliminate any remaining dents or warps.
Reinstall the deck once any corrosion or dents are fixed.
OBD Tools 365 Days Shop

did you break the deck belt?did you over load the electric clutch and blow the fuse?

There are a couple of causes for this. Is the blade height the same on the new mower? Higher blade height could cause a lot of the grass to be blown out from under the deck, and not into the catcher chute.

On the trailing edge of the mower blades is a small 'wing' for lack of a better term. There are two types of blades, mulching blades that have a lower 'wing', while catcher blades that have a slightly higher 'wing' but it makes a difference.

If the season has been hot lately, the grass may not be growing as fast, hence less clippings, and less dense grass could also cause this.

do you have the right blades for bagging ?is the deck belt slipping?

Clean out your chute also and don't let the catcher get so filled up, check it for readiness to empty more often.Don't cut wet grass that tend to stick and cause trouble. Good Luck...709

Change the blade from the mulching blade to a conventional discharge blade. They are quite different in design. Also, a cover plate on the deck will have to be removed in order for the new blade to work (plus the grass has to discharge somewhere,,,eg ,,,side or back.

can you tell me if unit has timmed blades and is the unit a rear catching unit ?


be sure engine speed is correct most applications this between 3400-3600 rpm
if unit has timmed blades - be sure that the blades are timmed correctly , and the correct blade is on correct side

if not timmed be sure blades are sharp and balanced , make sure the wing turn up is ok ( blade speed and turn up creates air velocity)

make mandrell vents are clear if unit has them , make deck belt is not slipping, and is not damaged
make sure deck belt tension is correct

make sure pulley splines are ok and are fixed tightly to spindle shafts and keys are in place

make sure the catcher vents or bag are clear and air can flow through,

lastly be sure that the deck is set level side to side and the deck has between 5 - 10 mm rake that is the height of front of the deck is 5- 10 mm lower than the rear of the deck
and the deck lifts up evenly

note let me know model and spec number of ride on mower
will try and help further if this info does not help

cheers paul46

Ranch King is a brand name of the manufacturer MTD.

Product manuals with part blow-up diagrams are available from MTD's web site,
http://www.mtdproducts.com/
Models are identified from the model number printed on a label under the mower seat.
The PTO and deck drive belts are shown on one diagram and the transmission drive belt is shown on another. The Form number on my printed Operator's Manual is 770-10526A (22HP, 46in cut) for Hydrostatic 817/818 models.

Parts can be ordered directly from MTD or other distributors on the web.

It is my experience that original brand name MTD belts work best.

The 22HP, 46" mower deck Ranch King Pro has 3 belts:

The drive belt which runs from the engine pulley back to the hydro drive unit to provide over-the-ground propulsion is part #754-0349.

A mower has either an electric PTO or a manual PTO, not both.

The electric PTO belt the provides power to the blade deck (runs around the electric clutch on the engine shaft (activated by electric switch, not the mechanical hand lever that engages the mower deck) is p/n 754-0476 for the 46" deck.

The manual PTO belt the provides power to the blade deck (runs off the pulley on the engine shaft (activated the mechanical hand lever to the left of the steering wheel that engages the mower deck) is p/n 754-0228 for the 46" deck.

The deck belt that goes around the 3 blade spindle assemblies on the mower deck, to drive the grass cutting blades is p/n 754-0349

In my experience, the PTO belt lasts about half a season, the other belts break about every other season when mowing 4 acres weekly.