it would appear so. W12 in hg @idle might go with Holleys recommendation of half that which'd be 6 (for starters) more on that later. I'm not sure if this is a valid test on a 4 corner idle setup but turn all 4 idle mixture screws in until they are lightly seated & count # of turns if need be to easily return them to where they were when you are done) and see if it dies. If it'll still idle it's a dead giveaway the the PV is open @ idle and it should not be open then. Float levels have already been checked right?