1999 350 Big bear Muniki Carb issue

[Georgetown William]

I have a 1999 Big bear that uses the newer style muniki carb on the atv. My problem I have been having is that it will start first lick and idle all day, but as soon as you try to throttle is up, It imediately cuts out to the point if you dont let off it will die. This is the first atv I have had that has this carb, so unsure exactly how it operates.
With the air box hose off and watching the operation as I try to throttle it up, the air valve never attempts to open or open the main jet needle.
My initial thought is that air valve assembly that is bettween $100-$150 is bad, but before I throw parts at it, is there something else (air cut off valve??) that operates the valve diaphram assembly and causes the system to open.
Any opinions or other things to consider, it is also somewhat intermitten, it sometimes will run fine, but mostly boggs out and starts to flood out. Thanks