Re: Tuning help
The factory W-31 cam is VERY low on vacuum. So much so, that there were no primary metering rods in their QJets from the factory .... just jets. My bet is on the power piston spring for the primary metering rods ......
That cam might have 6" of vacuum on a good day. If the power piston spring is for a higher vacuum cam, the spring will hold the rods out of the jets, giving a false transition from idle to primary. ie - the engine doesn't have enough vacuum to pull the rods into the jets. The power piston spring has to overtake the primary metering signal to pull the rods out of the jets. That is your idle-to-primary transfer circuit in the carb.
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