Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem
Carb stumbles just past idle
jupiterbandit:
I've just attempted to rebuild a 76 qjet for an olds 403.
I accidentally bent the arms on the power piston assembly and may have bent them down causing the carb to run too lean?
It idles beautifully at 800rpm. As soon as I slowly depress the gas pedal it starts to stumble.
The ATP is adjusted 2 turns out. It can move a total of 3 turns out but no more.
I also bent the float to sit 3/8" down in the bowl. It may be a hair deeper. I was having problems spitting gas up through the vent and soaking the airhorn gasket at 1/4" so I went deeper. The book says 13/32nds
So I am guessing that either the arms on the power piston are bent down too much causing me to run lean or the float is set too low?
If I stomp on the gas it will spin the wheels and then stall out as soon as I let off the pedal.
I'd appreciate any help you guys can offer on this one.
Cliff Ruggles:
Did you use one of our kits?.....Cliff
jupiterbandit:
Yes, I used one of your kits and your book.
jupiterbandit:
Carb is 17056256
It was made in 1975 for 1976
I have a 1979 Trans Am with an Olds 403 all stock.
jupiterbandit:
Damn, I messed with it again. I had taken it apart. Made sure both metering rods were entering the jets at the exact same time so I know they are level. I fixed the float issue so now it's not over flowing and Then I just had to screw with the ATP screw. I turned it 1.5 turns out.
So I put it all back together, fired it up and the stumble was gone. I grove it 200', the choke was cracked open and it was running awesome. The car was begging to smoke some tires. No stumble at all. Then the choke opens all the way up and it's not wanting to idle for nothing. It's acting like it's misfiring. I push the choke closed and the idle jumps up and it seems to run smoother but only with the idle mostly closed.
Is the ATP screw in too far? or is this a whole other issue?
Navigation
[0] Message Index
[#] Next page
Go to full version