Jump to content

Vote for Tractor of the Month
Garden Tractors and Parts on eBay

- - - - -

Jd Lt166 Deck Belt Problem

  • Please log in to reply
12 replies to this topic

#1 gto6570 OFFLINE  

  • New Member
  • Member No: 35722
  • 0 Thanks
  • 3 posts
  • Location: ok

Posted May 15, 2013 - 05:15 PM

I recently bought a '98 16hp LT166 with a 46 inch deck on it at an auction. I'm having a problem getting the deck to engage. I've checked the belt and it looks brand new, is routed correctly, and it is the correct one. There seems to be a lot of slack in it even with the PTO lever engaged. I've adjusted the linkage for the PTO forwards and backwards and nothing really seems to help. Sometimes the deck will kick on but it seems to need to build up speed for a few seconds to get up to what I would could consider normal speed and if I hit any high grass it will bog back down. I've checked all the pulleys and they spin clear and freely without any wobble or anything. Its not throwing the belt it just doesn't seem tight enough. I'm at a loss as to what to do



    God Bless Those Who Served

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 802
  • 26,697 Thanks
  • 28,342 posts
  • Location: N. W. PA

Posted May 15, 2013 - 05:21 PM

Welcome to GTTalk

Hope one of the JD gurus have some answers for you


  • Senior Member
  • Member No: 16399
  • 876 Thanks
  • 1,170 posts
  • Location: N.W. Arkansas

Posted May 15, 2013 - 06:49 PM

If all the parts of the deck itself appear to be in good shape you may want to give it another look over. For one thing I'm not sure I understand the problem from the way you explained it. If I am wrong I would like for you to try another little test. I am looking at the battery, take it to just about any auto parts store and request they do a load test of it, if it is bad it will show up and that will be a part of your problem. Do remember that what was a new battery just a short time ago could be a  bad one now.

 Let us know how you are making out.



  • gto6570 said thank you

#4 BairleaFarm OFFLINE  



  • Senior Member
  • -GTt Supporter-
  • Member No: 8328
  • 1,201 Thanks
  • 1,725 posts

Posted May 15, 2013 - 07:01 PM

Does that style have the pto cable that goes to the deck?

Sent from my HTC One VX using Tapatalk 2

  • gto6570 said thank you

#5 gto6570 OFFLINE  

  • New Member
  • Member No: 35722
  • 0 Thanks
  • 3 posts
  • Location: ok

Posted May 15, 2013 - 07:27 PM

JRJ - Sorry I kind of over explained it. Basically the mower deck isn't engaging when I flip the PTO lever. Sometimes randomly it will work. but it sounds like the blades start out slow and slowly start to build up speed. It acts like the belt is loose but it is brand new and the correct one for my LT. (Routing is correct) As far as the battery goes, It is brand new also. The engine runs like a dream, just can't get the thing to mow. 


BairleaFarm - The PTO for mine is a linkage made up of a rod and spring. 

#6 Arti OFFLINE  

  • Senior Member
  • Member No: 11282
  • 1,266 Thanks
  • 956 posts
  • Location: South West Wisconsin

Posted May 15, 2013 - 07:58 PM

I  don't know what model of deck that you have but I believe that it has 2 belts, one is under the cover on top of the deck and goes to the individual blades, it is possible that the second one that is giving you problems.

  • boyscout862 said thank you

#7 crittersf1 OFFLINE  


    GT Lunatic

  • Senior Member
  • Member No: 26142
  • 4,119 Thanks
  • 5,669 posts
  • Location: Newport, N.C.

Posted May 15, 2013 - 08:08 PM

:welcometogttalk: :wewantpics:

#8 boyscout862 OFFLINE  

  • Senior Member
  • Member No: 8923
  • 9,516 Thanks
  • 7,379 posts
  • Location: N.E. Connecticut

Posted May 15, 2013 - 08:17 PM

Welcome to GTT. Check out our manuals section for free downloads. I agree with Arti, check the other belt. Good Luck, Rick

#9 gto6570 OFFLINE  

  • New Member
  • Member No: 35722
  • 0 Thanks
  • 3 posts
  • Location: ok

Posted May 15, 2013 - 11:15 PM

Unfortunately there is only one belt for the mower deck. Its not letting me post pictures or links for some reason but I was trying to direct you guys to a picture




#10 dcrain5454 OFFLINE  

  • Member
  • Member No: 69931
  • 0 Thanks
  • 1 posts
  • Location: OK

Posted April 25, 2015 - 09:20 PM

I am having the same exact problem. Did you find a resolution? Same year, same model. The belt is brand new OEM belt, and there is a lot of slack in the belt even with the PTO engaged. The belt is routed correctly. Any help would be great.  :D

#11 poorpilgrim OFFLINE  

  • Member
  • Member No: 74067
  • 0 Thanks
  • 1 posts
  • Location: east kentucky

Posted August 09, 2015 - 11:43 PM

I pulled my deck off today.  I'm researching the same issue.  There is a bracket on the lower end of the engagement rod that vibrates until the hole is egg shaped.  I was advised that a second nut on the upper end of the engagement rod would mitigate this issue, but when adjusted right there isn't room for a second nut on top.  The egg shaped hole creates considerable slack.  My adjustment rods are fully extended.  Also there is a spring(s)  that is associated with the engagement rod and adjustment can be made to the front of the deck by twisting the nut between the front tires.  After sharpening the mower and greasing the plugs, I reckon my next move is to buy a shorter deck belt.  lt 166 46" cut 1999 model

#12 Anttiajt OFFLINE  

  • Member
  • Member No: 83377
  • 0 Thanks
  • 1 posts
  • Location: N Illinois

Posted July 21, 2016 - 08:12 PM

I acquired a lt 166 from my dad and am having the same issue as poorpilgrim, no more adjustment left and belt is still loose. If I engage super slow it'll cut but I can't disengage slow enough for it not to throw the belt.
Did anyone figure this issue out?

#13 stacyg OFFLINE  

  • Member
  • Member No: 83427
  • 3 Thanks
  • 5 posts
  • Location: Wellman iowa

Posted July 22, 2016 - 09:43 PM

My parents used to have a LT166 with the 46" deck. IIRC, they used to have issues with the belt not engaging the blades like it should have, but a new belt always fixed it. The belt would look ok, but it was like it had been stretched enough and there wasn't enough adjustment to take up the slack. But if the belt is new, it shouldn't have a problem engaging the blades. Have you checked to see if the brake pads for the pulleys are adjusted right? If they aren't, they might be dragging too much. Also check the linkage for the brake pads, could have sloppy linkage, or pivot that does not move. Also I seem to remember replacing the bushing that the belt idler is on. Hope this helps!