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Old 12-30-2012, 09:53 PM
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Quote:
Originally Posted by JJWBuck View Post
Hello everyone this is my first post here on the forum and I have several questions about a quadrajet carb. I have a '79 chevy with a 350 in it. With a 4 bbl carb ontop of it. The engine has been sitting for years without being started. I threw in a rebuild kit for the carb and got it back on. The process to get the engine running wasn't hard.

My questions:
1. The choke lever is always stuck, when I hit the gas the lever sticks into a position and does not lower. The only time it lowers is when you tap the gas really quick, or manually pull down the lever. The lever never goes down because of the bog. Is this normal?

2. When I tap the gas slowly, it runs fine. In the upper RPMs it begins to bog and pop. If it's in drive it will bog down, if you keep on the throttle it will just stall out. What are the possible causes to this?

3. When you hit the pedal it just bogs down for a second, then kicks in. I tried messing with the idle and fuel screws but I'm totally new to this. Any tips on how to tune it/or any good sites to look off of?

Sorry for the questions, especially the q-jet experts.
Any tips are greatly appreciated.
-Thanks
When you say "lever" are you referring to the choke flap in the airhorn, or the counterweight on the side of the carb?

Do you have a divorced choke (no round choke housing on the side) or do you have an integral choke (either hot air (examples below) or electric)?




The rod that runs from the choke down to the choke housing (if integral choke) or the choke linkage (if divorced choke) is a bear to get aligned right. Are you sure this rod and the small bottom link (shown below, before being assembled) is assembled correctly? The rod can even be installed upside down with enough effort- but it will not work right.




Hard to say what the higher rpm loss of power might be, but assuming it's from a loss of fuel and it's not too rich (if too rich the exhaust will be black and smell of fuel) one thing will do it if you're actually into the secondary circuit, and that's the small wells the secondary discharge tubes sit in going dry (locations in image below). They're fed by a small orifice from the main fuel bowl, and if the orifices are plugged, the secondary side won't work right. Click on image for more info.




But if this is happening in the driveway and not with the engine under a load, it could be the float level too low, or even a plugged fuel filter (there's a filter in the fuel inlet of the carb unless it's been removed).

The timing could be a problem, but it shouldn't stall due to timing.

Check for vacuum leaks. Best to disconnect the vacuum lines (mark them first) then cap off the vacuum ports and see if this makes a difference. If this helps, reattach the hoses one at a time to find what is causing the vacuum leak.

Last edited by cobalt327; 12-30-2012 at 10:16 PM.
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