Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Freshly rebuilt carb running ruff

<< < (3/3)

Kenth:
With proper main jetting for the current main air bleeds there would be no difference in fuel economy compared to smaller sized main air bleeds and main jetting.

Idle bypass air holes is located in the throttle plate, under the throttle blades, and is not a direct part of the idle mixture circuit air bleeds.

The choke channel in carb pulls hot air thru the choke housing for the bimetal spring to open the choke. This is not needed when converted to an electric choke element and the channel should be closed in bowl or at air inlet on choke housing.
The loss of this added air is compensated by opening the idle air bypass some.

cj7:
I already plugged the choke, but i will open up the bypasses. This should lean out the idle? anything else i should open up for performance besides the secondary POE?

Kenth:
Opening the bypass air will lean idle mixture some but most of all it will reduce throttle blade opening angle at idle reducing the possibility of mains nozzle drip at idle.

,055" idle mixture needle holes are somewhat small, i like to have them .080"-.085" for better control on these units.

Did you use the "tip-in" method to check cruising mixture at 2200 rpm

Cliff Ruggles:
Adding idle bypass air can "lean up the idle" simply because it lowers the angle of the throttle plates and can expose less idle transfer slot.  This puts LESS idle fuel into the engine at idle if you don't move the mixtures screws.  The added air doesn't lean it up as some folks think as it still gets the same amount of air to maintain the same idle speed just pulling it down thru the carb and not re-routing it in from the bypass system......Cliff

cj7:
Thanks for all the help. And yes I was using the tip in procedure. I'm going to go ahead and use the 76 jets and make open things up as suggested. Opening up the body main air bleeds all the way to .120 does seem like a large jump, considering they were originally at .066. I will let you all know the results after.

Navigation

[0] Message Index

[*] Previous page