Troy-Bilt 17.5 hp lawn tractor. Drive belt adjustment? Anyone?

I only come here for help if I cannot find the answer elsewhere after searching for an hour. My hour is up!

Anyone know how to adjust the drive belt on this thing? It is a two year old mower, maybe three. It appears that the smaller belt that goes to the rear differential is the culprit, but I cannot find any adjustments on it.

Google search shows that this is a common problem, but no answers that fix it.

Anyone have experience with these things?

It will not engage in gears 1-3. Will engage in gear 4 if level, no incline. Higher gears work, I assume because the belt is slapping around enough to grab the pulleys as it slips by.

Not right, and need to fix it before I wear something out.

 

Sounds like a MTD built mower. Does it have the stupid sliding center pulley? One belt comes from the engine to one half of the pulley, and another belt fits on the other half and back to the transaxle? If it does, the pulley is your problem. The are notorious for rusting and freezing up and not sliding. The center divider of the pulley is supposed to be able to slide up and down, thus lengthening one belt while shortening the other, thus changing the ratio, or speeds. Piss poor design that only works when it's new, then causes lots of problems. If you can get the pulley off and sand the center shaft and oil it real good, it should work right for a while. If it won't unstick and slide up and down, you'll have to find a mower shop and get a new pulley.

 

That sounds like it. A long belt back to the rear of the mower, then another belt above it to the rear end. There is a spring on one of the pulleys, like it is supposed to move. That must be the one you are talking about. The spring is just flopping around, not serving any purpose, right now.

So I need to get that thing freed up, if possible, and it should self-adjust. Right?

Mower spent all of it's life 2 blocks off the beach, so not much of it isn't rusted up, but I should be able to squeeze another year or two use out of it. Our new house has nearly 1/2 acre back yard. Not fun with push mower and flip flops. 90 degree humid south texas heat.

 

Well, I yanked that spring off and mounted it to something a little further away, and that helped a little. But then put it in gear and the main belt is slipping, too. So I pulled the rod off from the clutch/brake pedal and ran the adjustment out WAY past full adjustment and it helped a little more.

I have decided that the belts are shot. I think new belts will make a world of difference.

 

When you get the new belts, it should help if the old ones are stretched. That sliding center of the pulley sounds like though it's not sliding, thus when you move the gear selector, the whole pulley moves as it should, it just isn't adjusting the ratio of the pulley halves. That's why one belt is tight and the other loose. If that center slides like it's supposed to, when you change gear, both belts stay tight. That gives you different speeds with a single speed transaxle. MTD has used that system for years, and they bought out Troy Built a few years back and changed all the Troy Built mowers to their system. I think MTD has a website you can see a diagram of the drive system.

Oh, and a 1/2 acre is just a start for me. I've got probably 2 acres total in yard. I can cut all of it with my 1985 Craftsman 44 inch cut 16 HP in about 1.5 to 2 hours.....

 

Scoop, look at this diagram and see if this is the way your pulley system is set up. I just guessed at the model, but most all MTD built mowers are built this way. Number 83 is the variable speed pulley that gives so much problem.

http://www.troybilt.com/webapp/wcs/stores/servlet/ARIPartFinderView?langId=-1&storeId=10001&catalogId=14102#/Troy-Bilt/13AV60KG211_Bronco_%282008%29/Drive_System


Looks like that pulley sells for $50.28

And if you replace the belts, it's best to replace them in a matched set.

That pulley system is the reason I won't ever own another MTD built mower. I've had two or three, and all gave problems with that pulley. I'll only buy Craftsman or John Deere mowers from now on. Craftsman is made by AYP [American Yard Products] and has been all along. Easy to get parts for and much better design, IMHO.

 

YUP. Looks like it.

This was a free mower. So not complaining if I have to spend a couple hundred to keep it running for a few more seasons.

It is pretty rusty, from life near the beach, so I may just swap the belts and milk it for another year, and buy a new one. I doubt the deck will make it much longer than that before it rusts away.