Hey guys got a 70 lark with 4 barrel q-jet. It has a large problem right off idle, it will just flat on its face and almost die if you get into it. Are my secondiries not big enough or too much or what is the deal? I heard something about a control to slow down the opening of the secondaires. I adjusted it to the maximum i could with the vaccum screws. Lemme know Mack
I would think this would be more of a problem with the accelerator pump rather then the secondaries, since they don't do much just off idle. Try this, take off your air cleaner and look down into the carb, when you quickly open the throttle you should be able to see a strong stream of fuel in each barrel. If not, then your accelerator pump needs to be looked at. If you still want to mess with the secondary air valve there is a small screw on the passengers side about where the linkage hooks up to it. There is a small allen screw below it too. Loosen the allen screw while holding the small slotted screw on the side once the allen screw is loose you can turn the other screw to loosen or tighten the valve, in makes it open later, out makes it open sooner,but only do it in 1/8 turn incrememts to fine tune it. Once you have ti where you want it, tighten the allen screw but don't release the slotted screw becasue the spring will unwind it. Good luck in fixing your problem btw, what do you mean by vacuum screw?
Knowing when the bog occurs. If it occurs before the secondaries are engaged, I would be looking at either the accelerator pump or the power piston sticking. After checking the accel pump by using the previous posts procedure, I would check the power piston as noted in a previous post. Qjets are infamous for this, and will cause the symptoms mentioned.
