Quote:
Originally Posted by joem1021
my vacuum advance is on the drivers side rear metering block. does that make a difference? thanks for your help
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Evidently carb has been converted to four corner idle using a front metering block, so it may not get proper ported vacuum on rear block.
The vacuum passage, for the front metering block, starts right above the right front throttle blade. Primary part throttle opening (cruise) provides vacuum to passageway.
If vacuum passage on rear block works ported, secondary throttle blades would have to partially open to provide vacuum to distributor. With secondary throttle opening vacuum starts to drop.
Anyway back to your question, for vacuum advance to work properly, it needs to be hooked to primary (front) end of carburetor, for cruising. Vacuum advance is for cruise only. Vacuum in intake drops near WOT and vacuum advance doesn't work.
Hope that makes sense.