That makes sense about the water vs. fuel/carb cleaner.
The hole in the float is somewhere mid-height on the inside of one of the cans and so it needs to be fixed. I can generally tell where it is and might be able to guess where to add some solder, however maybe that would add weight and change the height of the float? Any tips on how to solder it - glob it on the inside to make sure I cover the hole? or is it better just to get a new float?
You might be better off to try and seal the hole with JB Weld or Seal All rather than trying to solder it - my experience has been that unless you can get the brass extremely clean the solder won't seal the hole (or crack) all the way around and by the time you have done two or three soldering attempts there will be pieces of solder inside the float making it heavier. If you can afford it I would recommend purchasing a new one (or a good used one) as that would probably be for the best if you are planning on keeping the tractor. I believe the float is still available new but check with Bolens 1000 (Bolens Parts And Supplies) (or a local supplier) as it has been a couple of years since I last inquired about one here in Canada.