[Woodz428]

Typically, you get a bog, not a surge when the secondaries open too soon. If it surges,as in picks up some acceleration, then it is probably pretty close. The bog is a drop in power, because the engine isn't ready for that much opening. I don't even think it is an issue much with double pumpers if the pumps are adjusted correctly, mostly with vacuum secondaries. Having said that, I was actually wondering if he meant when the primaries on the secondary carb opened? They have a progressive linkage. It is also pretty important to put a balance line between the 2 secondary vacuum tops. There are special tops available, they keep the secondaries on both carbs operating together. Without the balance line it's possible to have the secondaries open on the primary carbs, then drop closed again when the secondary carb primaries open and the vacuum signal drops. Under mild throttle conditions this can create a less than linear acceleration and weird carb actions.