I recently adjusted my carb, and about a week later went out to drive it. I put it at 2nd at about 45, floored it and the motor finally "woke up" around 65-70 mph. My motor is a little peaky as it is with the single plane intake and cam, but it was redicuclous. So I remembered what I did, I thought I was bogging, so I tightened up my AV valve. Sure enough, after i did, no more bogging. But I finally realized as a last ditch effort (I was ready to rebuild the damn carb I was so mad) maybe it isnt getting enough air to the motor. So I go out today, loosen the AV, and hit it cold. Yep, it bogged. Warmed up a little, floored it from near a stop, pulled right through 1st and second without stumbling. My secondaries had so much tension they would try to close when accelerating and the motor didnt create enough suction till about 4500 rpm to hold them open. Anyone experiencing stumbling or not wanting to rev like I did, try loosening up the AV valve. Before you spend hours looking around for a solution on a message board, try simple things

 

mine did the same thing until i loosened the AV tension....

 

Most secondary rods are very lean on the "taper" part. You need to get them quickly down onto the power tip part of the rod or you'll have a kind of "perpetual bog." You only get down onto the power tip when the air valve is almost fully open. This is especially true on a modified motor with bigger intake, lumpier cam, etc.

Most Qjet will work just fine with as little as 1/3-1/2 turn of twist on them beyond the "zero tension" point. If you get over 3/4 turn you've gone too far in most cases.

 

Damon, thanks for the tip. I am going to try really loosening the AV flap and trying the 45-70 test in 2nd I do to test the carb. I know Ive got enough motor to take advantage of the full force of that carb. I am currently looking for new rods and hangars for my carb. The perpetual bog, maybe thats why my car feels so much faster from a stop than from a roll. From a roll my car sucks, but from a dead stop run through the gears this thing is a beast. Ill try really loosening the thing up tonite.

 

Okay guys... some of us are serious noobs. What is an AV valve, and
where would I go about adjusting it? I am currently having this
problem. Car runs GREAT at 1/2 throttle, but put any more than
that, and it just bogs itself to death.

The only thing I know about AV.. is Audio Video... hehe.

~castrol

 

Okay, let me think on where exactly the screw for it is. The AV is the flap over the secondaries (its the big flappy thing towards the passenger compartment), and this allows air into the carb. Your tension is probably too little. To adjust this tighten the regular head screw (most on this carb are torx bits). This screw is located on the passenger side of the carb towards the back of the carb. It is near on of those bent metal rods (idle cam or something, i dont know) and you may have to jiggle that thing a little to get a clear shot at the screw.

 

By any chance, do your report cards say something like, "Has difficulty following instructions"?

The sticky at the top of this forum titled "Welcome to the Carb Board; Please Read" (emphasis added), has this link https://www.thirdgen.org/newdesign/t...adrajet.shtml, with this title "Tuning for Performance with your Computer-Controlled Quadrajet". It's all in there. The secondary tuning parts (read: AV) also applies to non-CC q-jets.

 

My report cards always said that. They also said "inability to pay
attention" along with "does not play well with others."

Thanks for noticing.

~castrol