what is wrong with my mtd 20HP 46"?

I had the same problem...belts breaking repeatedly. After a few times I took it to Elson's in Indianapolis. They straightened it up and fixed it. Works like a charm now.

Mike
July 2013

Try replacing the upper deck drive belt with a 5/8"x91" belt. That is what I did with mine. I may have to go with a 92" belt but I will not know until I replace the blade brake on the deck. The 1/2" belt that is stock is simply to small for the load it carries. You may have already noticed that the belts for the transaxle are 5/8" belts and that the pulleys on the deck are sized for 5/8" belts. The secondary blade drive belt (lower belt) seems to hold up just fine so I would leave it as the stock 1/2" belt. I have also had many of the other issues people are reporting like the broken 3/8" pulley tensioner bolt.

Upset with MTD
April 2012

upper idler pulley is out of alignment. edge of pulley bites into the belt.

mark bee
March 2012

It's a piece of junk. Have Yard Machine 601 with 20 HP 46" cut. Motor rebuilt once, Transaxle replaced once. Belt above trans axle 3 times, drive belt twice, broken tensioner bolt 4 times , broken springs at least 6 times, double pulley set up on deck 3 times. Went to cut grass today broke 3 times. Now parked in my shed.
Purchased from Home depot, absolutely no help from them.

Mark in Sorrento Florida
September 2011

i have the same model, is it the upper deck belt you are talking about, if so look at the idler pully bracket is it bent, straighten it out and should solve the problem

j rotondi
May 2011

its junk i have one and it keeps breaking springs bending pulleys breaking deck belts now the transaxle is leaking grease. been in the shop 6 different times for deck issues also cant keep the deck adjusted i am currently trying to get mtd to replace the whole unit but no luck so far they just want to fix it they have already spent almost $900.00 on a mower i paid $1300.00 for.

joridan from winchester va
September 2008