I need a list that causes the car to bog from the most common to the least common reason. A way to fix each cause would help too.

I have a bog at about 1/2 throttle if I punch it on a 30mph roll.I think I need to change the advance curve(wieghts/springs) since mine is all stock right now.

Daz

 

Q-jet, Performer/AFB, Holley/Demon VS, or Holley/Demon DP?

 

1. A lean condition

2. Not enough fuel for the amount of air

3. Driver opening the throttles too far too fast (letting in too much air) causing a lean condition


Fixes:

1. More fuel

2. More fuel / driver education

3. Driver education

 

just a few thoughts, plus the above replies....

carbon build-up in spark plug gap

clogged carb jets?

bad accelerator pump?

 

choke pull off perhaps? might be opening up too soon, hence too much air.

 

On the way home yesterday the car was stalling.So I richen it up the RPMs went back up.So I guess it was running lean.I can still feel a bog at around 2500 RPM though.I set the idle mixture on the highest reading before.I guess the car wasnt warm enough when I did it.

4160 Holley 800cfm

Daz

 

If the car wasn't warm enough when you adjusted the idle mixture screws, it would be too rich when warmed up.

You seem to be describing several different problems. "Bog" is typically defined as the engine not picking up when going WOT at low RPMs. It is not related to mixture ratio, but the secondary throttle blades opening more rapidly than the secondary metering circuit can supply fuel.

You could very well have a combination of idle mixture, primary metering, primary enrichening, secondary metering, secondary opening rate, and ignition timing all being out of wack.

The carb may be too big to boot.

 

Repeat after me..... "All bogs are lean bogs..... All bogs are lean bogs."

Say that 20 times every night before you go to bed for a week. Get it in your DNA.

It's not always true, but 95% of the time, it is. Accelerator pump system not providing enough fuel, secondaries opening too quickly, etc. It's almost always going to be a lean condition if it bogs and then goes like a bat outta he11 a second later.