secondary blades

[91Burban]

I understand they are vac operated but also has linkage from the primaries
 what happens when the primary closes and the secondary stay open?  is there a fix for this?

[Cliff Ruggles]

The secondary throttle plates are mechanical only, not vacuum operated.

Some models use a spring if they have a choke lock out on the other side of the shaft.  If the spring isn't installed correctly they may not close once opened.

They can also stick open if they get gummed up with carbon.  Might want to try some carb cleaner to the shaft on both sides, compressed air, then apply some lubricant like WD-40 to make sure the shaft is moving freely.....Cliff