Put a diesel in it and use the belt.
LOL, the K321 runs great and seems to be pretty new... it's the rear hydro that I am more concerned with. It's 45 years old and doens't really seem as fast as i would expect. I would love to put a diesel in it though :) I watched your repower with that 12 and it is badass!
The round piece sticking up to the left of the hose is a "tow valve". It needs to be in 1 direction to "tow" the tractor, and turned 90* for the hydro trannsmission to work properly. Yours looks to be somewhat rusted, so you better soak it with penetration oil.
It does not turn tight to work, just like a ball valve....90* turn for open/close.
Yeah, that's the reason I snapped that picture. I new it was the tow valve but I wasn't sure if it was supposed to tighten down like the JD 140's does. It actually turns freely... I just use a pair of pliers.
The only thing I'd like to add is you need to turn the valve 180 degrees. It should have a 1 1/2" long roll pin in it to use as a handle and indicator. it should be flush in the shaft on one side.
This brings me to my next question... it doesn't seem which way the valve is turned, it doesn't have any effect on the performace of the hydro. I only tried it in a couple of different positions though.
So, when I replace the roll pin how do I know which way the exposed end faces???