Tractor Repair: Ford 600 tractor, valve clearances, valve cover

Question
I found out that the valves on number four cylinder were out of adjustment. Not by much but as soon as i moved them it started to fire. The book said to adjust them to 0.15 should this be done hot and running? My book just said if have just put the engine back together set them at 0.15. Thanks

Answer
  When you first asked about this tractor you stated that you removed the valve cover and checked everything underneath, so I assumed you had already checked the valve clearances.  I don't see how the compression could be equal on all cylinders if the valves were not adjusted properly.
  Anyway, unless specified otherwise in the instructions, valves should be adjusted with the engine cold and not running.