If/when the zilla kicks back on you, you WILL break bones with out a boot.  Own a zilla long enough and it will kick back on you.  I just had another zilla I was borrowing kick back on me at Glamis.  Even with my boot on, I still had a limp for about a week.  This zilla is mostly stock and it still tried to bite me!

Good Luck
Larry

you the know the worst part about kick back is not was it does to your foot -although I've had many black and blue bottom feet -, it's when it sends your knee crashing into your thumb throttle.  That will make a grown man cry.

The PV wont prevent it from starting.  It's likely a jetting issue.  Also, if you're getting kick back, something else is wrong.  Either some arrows arent lined up on the clutch side or your stator isn't lined up correctly and is advanced a bit.  Zillas are really hard to start if the jetting is off.  And start within 3 kicks or so when it's spot on.

If you dont have one already, get a repair manual.  float height setting should be in there.