General Category > Quadrajet Carb Talk and Tips
Hesitation when taking off
Kavesh:
Thank you
Kavesh:
Just a quick update, the carb no longer has the hesitation on take off, so that is good.
New problem though, after assembling and starting up, she was idling smooth and strong with the idle screw just touching the primary stop. (not sure what its called)
After about a mile of driving I stopped at a traffic light and the idle was really bad the motor was very rough and shaky. Once above idle the carb performed beautifully.
I suspect there is some dirt in the idle circuit that may have dislodged and caused a blockage.
I don't think its dirt from my tank or lines as I have a nice big fuel filter in line before the fuel pump and its clean.
Kavesh:
I have pulled the carb apart again and there was no dirt inside. It was clean.
In any event I went through and cleaned again just in case a passage was blocked. This time I even removed the idle tubes and they were clean. I also pushed wire through all the opening.
Sadly though I am still with this terrible idle. When I start up it is fine and as soon as the motor starts to warm up, and you go around the block the poor very rough idle returns. I can confirm there are no vacuum leaks.
This problem began when I swapped out the float bowl as I was not getting a good squirt from the previous bowl which seems to have improved with the bowl in question now, the hesitation is no longer present.
I am wondering whether there may be an issue with the float bowl. I was told by a buddy that perhaps there is fuel leaking internally on the idle circuit.
Please help me diagnose this. I have opened the carb so many times now, the airhorn gasket is looking a little tired now :(
Kavesh:
btw my carb number is 7029282 which is an Australian Holden 308 V8 engine carb.
Kenth:
How far out are the idle mixture screws for best vacuum/rpm?
Can you have the engine run worse with screws further out from best lean idle?
How much vacuum in intake at idle in neutral and in gear (A/T)?
What rpms in neutral and in gear (A/T)?
All of above at normal operating engine temperature.
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