Is there a known trick to removing the bolt that holds the water pump impeller? I tried wedging a penny between the housing and the impeller but that didn't work - there was anything to "catch" and lock the penny. I can't find a universal that will allow my 1/2 drive impact wrenchy to accept a 1/4 inch socket and lastly, I can't locate a 8mm (I think this was the size, although it could've been smaller) socket that is 3/8 drive.
I finally got it off by holding the impeller with a strap wrench but bent the blades in the process.
It's even more of a challenge using a torque wrench to put the thing back on to the required specification. (I'm not sure if I got it to the correct specs)
I suppose the question doesn't just pertain to the KX65 but to any bolt that keeps spinning and you can't use your impact wrench because it's too large to work.
thanks.

Unfortunately, because of the design on that whole shaft/gear assembly, it's best to just use an impact gun. Use adapters to get it down to 3/8 or 1/4 so you can use your sockets and spin it off - the speed of the impact gun pretty much breaks the stiction of the nut on the shaft and spins it off - won't damage the blades either, then just use an impact gun with the air feed turned down to 70 lbs to get it back on.