Belt routing illustrations

The parts manual has a diagram

https://www.weingartz.com/illustrated-diagram/john-deere-parts-lookup/model-x300r-tractor-select-series-with-42-inch-rear-discharge-mower-deck-pc9608/4275-36371

Or How-to videos

Andy, Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
Zoom 42 mower deck belt routing diagram Google Search
http://apache.ariens.com/manuals/00173200.pdf
How to Replace the PTO belt on an Ariens Zoom Zero Turn
Ariens Zoom 42 Owners Manual

Do a search on goggle for the make model and deck size and you can see the routing diagram.

Make a drawing of the deck routing and pull the belt off the mower measure the width and length of the belt and order one on line or go to a mower shop with the belt and they can size it to the one you need. Do the same for the drive belt.

Go to Craftsman, Order Tree or Parts Tree.com and input your model number. Choose the correct tab and go to the mower deck. It will give you a good over view of how the belt routes. Hope this helps.

You can find the model number under the seat by the battery. With that number you can go get the belt at a local lawn mower repair parts shop. And with that number you can find the routing on an illustrated parts drawing by going to a lawn mower/ small engine repair parts website such as partstree.com or outdoordistributors.com. If you can not find it I can tell you, but I would like to glance at the drawing to see if the deck is the one that I am familiar with, so I would need you to send me the model number from the tag.

I hope this helps you get it done.

http://jdpc.deere.com/pimages/PU00/PU00859________UN28APR08.gif

Copy and paste this in your address bar and it should take you to a picture of how to route the belt

do you remember the routing of the belt? there should be a diagram on the deck somewhere - best thing to do is rout the belt while the deck is lowered, leaving the loop at the front to put around drive pully on bottom of engine. once that is all hooked up, there are deck adjusters on either side of the deck - that you can adjust to relieve some of the tension on the belt - turn the adjusters clockwise to tighten, counterclockwise to loosen - let me know if this helps or if u need more info - i have a 10 year old 42" deck tractor out in my barn and if need be, tomorrow i will walk u through - online how to adjust the deck

there will be a sticker showing the belt routing, on the back of the deck [rear] in the middle, or on the left, top side of the deck

The easiest way is to find your owners manual and find the picture of the belt in there. Using the picture as a guide you can change the belt in a matter of a few minutes. Just make sure that you get the new belt under all of the belt guards or you will destroy the new belt in no time. If the pulley is flat on the running surface, it goes on the back side of the belt, if it is a "v" on the running surface, the inside of the belt goes in the "v". There may also be a routing diagram under the foot board on one side or other of the tractor. Some of the AYP units have it, some don't