85 z28 stock carb 305 . it almost dies when flooring from a stop but is fine when at normal speeds. any ideas?

 

Welcome to the boards. Sounds like you are too lean or too rich.

May need to adjust your mixture.

 

Sounds like classic "quadra-bog" - the secondary air valves opening too quickly.

The opening of the AV is controlled by two things: An adjustable tension spring; and, the choke pull-off. Check out the tech article linked from the thirdgen.org homepage about getting the most out of your q-jet. It has a good description of adjusting the AV tension. The choke pull-off is a very good item to verify as well - it may pull in when the engine is running, but make sure it holds vacuum when blocked off (such as sucking on it with a vacuum pump - or by mouth . . .).

 

cant find that article?

 

If you look at the passenger side of carb, you will see linkage thats connected to the secondary air door. This linkage is connected to a vacuum actuater that draws vaccum from the front port on carb. You should check the hose from the actuator to the front of carb, sometimes they go bad and leak. if in doubt replace the hose since its only pocket change. With the engine started tug on the linkage to try and open the air door. If it opens easily then either the vacuum actuator is bad or its vacuum source is not routed properly or has a leak.

The engine falls on its face because the secondary air doors opening too fast. The secondary air door prevents the secondaries from drawing more air until the engine is loaded sufficiently. When the intake vaccum drops to a low enough level(loaded) then the tension on the air door is reduced and slowly allows the air door to open.

 

Guess we'll give you a fish, just this once. . .

https://www.thirdgen.org/quadrajet

 

Sounds like your accelerator pump is ripped.

 

If the accelerator pump was ripped, it wouldn't be fine in normal driving.

 

Yeah I will have to agree with you, however, it seems to me one of the symptoms of an accelerator pump beginning to fail is throttle response. Correct?

Besides it is a simple thing to check and wouldn’t hurt.

 

Five7 is right, its not the accelerater pump the carb just needs adjusting.