2000, 300 KingQuad 4w.d.

Just found this forum, and I like it!
Bought a couple of 300 Quads at auction.  Been sitting for a while, and carbs were gumed up pretty bad.  Cleaned one, works and runs great.  Cleaned second, and it  idles too high.  Idle adjusting knob has no effect on idle speed.  Hit throttle, rpms increase, idles down, then slowly comes back up.  It's not real high, but makes shifting a little tough.  Other than that, starts easily, runs great, no other problems.  Throttle cable adjustment is all the way down, and cable moves very freely.  Any ideas?
Also, I can't seem to find a manual that shows to cover the 300's.  Thanks everyone for any help you can give.  

Clymer manuals cover many many years of the King Quad.  Look for them online - you can find them just about anywhere.  

check the intake boot in front of the carb for leaks.
you can do this with starting fluid,  start the engine let it run get it to idle down, then spray the starting fluid around the intake boot.
see if it idles higher or stumbles.
sounds like an air leak to me.
however it could be the floats sticking.  sometimes when you clean em the needle valve will stick a little. try a second thorough cleaning if the intake boot isn't leaking.

when you clean it again mark where the fuel/air mixture screw is set and count how many full turns it takes to remove it.  make sure you clean the hole it came out of. sometimes those will get dirty and it wont idle right.
be sure to put the fuel/air mixture screw back in the same amount of turns it came out with and line up the marks you made.  
Keep it RUBBER SIDE DOWN!!