Troy bilt bronco mower will not drive fast

I have a 42" troy Bilt Bronco riding mower with auto transmission. The long drive belt that connects to the crankshaft pulley broke. I replaced the belt with a belt from lowes after giving them the model number and serial number of the mower. Although the belt appears to be on correctly, the mower moves very slow when the transmission is in forward, and the pedal is pushed all the way down. My model number is 13WX78KS011. The serial number is 1A290B70337

 

When you say auto transmission, do you mean varidrive or hydro? MTD has been calling their plain varidrive that they've made for decades an auto, but many people call a hydro an auto as well. If this is a varidrive like I suspect it is, the short belt may also need replacement. Also, the varidrive pulley bearings may be bad. These trannys also don't hold up long, and it may be a problem internally, but that is doubtful if it was working fine up to the point the belt broke... unless the belt burned in two. You'd most likely hear a whirring or grinding noise if it was an internal problem.

 

This is a varidrive. There do seem to be some play in the varidrive pulley. When you grab it by hand, it seems to have a bit of a wiggle to it. Not a whole lot, but there is some. I did actually have some concern about that wiggle, but didn't know if it was normal or not?

 

No, it should should spin freely but have no side play.

 

Thanks a lot for the help. I really appreciate it. I will go ahead and order that bearing.

 

There are two bearings there. They are 6203 bearings. Your small engine repair shop should have them on hand. They are the same as the upper mandrel bearings on most ayp (craftsman, poulan, husqvarna) riding mowers and several others. Should run you around $8-9 apiece.