Cranks good, no start / hard start engine cold or warm:

[fussfeld]

i'm sorry to write a book about this, but i feel this is the only way we'll solve it.

Background:
quadrajet
HEI ignition
Stock-ish cam---like 184/195 @ .50"---- so decent vacuum etc.

1) Prior to the no start/difficult to start problem, the engine would start cold within 1 crankshaft revolution if not less. Hot start was a little cranking and possible some pedal intervention---maybe 1/2 down. Still acceptable.

2) The ONLY thing i did IMMEDIATELY prior to the problem was to adjust the secondary throttle plates to open more. NOT the secondary air flaps, but the actual throttle plates. The secondaries really weren't opening at all when the primaries were at WOT. IMMEDIATELY after i did this did all the problems start.

So, in order to adjust the secondary opening, you have to adjust tab "A" towards the direction of tab "B." (i think?) More opening = more towards "B". Less opening, less towards "B." (This isn't the actual carb, but the linkages are all the same)

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i don't remember exactly, but this is very likely how i did it:

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So, what i THINK happened was i got "too enthusiastic" and pressed down counterclockwise on the wrench holding the throttle arm---in order to counter-act the forces of moving tab "A" clockwise towards tab "B."

But, in doing this what MAY have happened was that now tab "C" became bent----the throttle stop for the primaries----which means that the primaries are now closed more
than they usually are.

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i then experienced stalling and the only way i could keep the engine running above 1000 rpm was to keep my foot on the pedal---because of course the engine will stall when you take away either air, spark or fuel. i have since, probably, solved THAT problem by turning up the idle screw. But that's not important now because what good is that if i can't get it started?

So, where we stand now is the engine may not start cold---50/50 chance. And even if it does start, it doesn't start normally----more of a putter to start with lots of cranking. The engine WILL NOT start hot unless you wait at least an hour.

Here is a video to better illustrate: We see here at about 9 seconds we hear the electric fuel pump come on. Then at about 15 seconds, i give it a shot of gas. Then about 7 seconds of cranking and only when i press the pedal down---(look closely at the top left corner to see the accelerator pump pushrod move) does it start.

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What would this tend to indicate? Also, i know the choke flap probably shouldn't be flopping around during cranking. i have since fixed that, but it didn't make a difference.

 

[GMFORLIFE]

Unless it's cold out..that choke plate needs to be open.
Install a manual choke so you can make adjustments from drivers seat.

 

[GMFORLIFE]

That timing is off too.
You can tell by how it sounds.
Once you get it running..get the timing dialed in.
Should start instantly when timing is set correctly.
What do the plugs look like?

 

[GMFORLIFE]

Turning up the idle screw covers up your other problems.
Try not to make a lot of adjustments at once..youll lose your baseline.
Once you get the VEHICLE idling..the lowest rpm that will idle smoothly should be used.
An air fuel gauge in tailpipe would tell you a lot also.