[byoul]

I have a 72 with a 454. I've noticed that when I push the accelerator down to open up the secondaries in my 4 barrel carb, it feels like the car is going to shut off completely. The car usually loses power, jerks, and then sometimes starts to accelerate, or sometimes just slows until I take some pressure off the pedal to close the secondaries. If I've been driving the car for a while, say over 20 minutes, this problem sometimes goes away. But most of the time, especially within the first 10 minutes of driving, my car basically stalls when I put the pedal down too far. Any suggestions?

 

[6NOVA4]

usually either timing or fuel related as in not enough squirt from the accelerator pump. What 4 barrel carb do you have?

 

[racer77]

Accelerator pump. Are you noticing any gas dripping from the carb? If you very slowly apply the throttle,does it still do it?

 

[Chori]

it would seem that the car is too cold to be driving that hard? Another thing would be that you are running too rich, change the jets on the rear and test test test. make 1 change at a time.

 

[6NOVA4]

yea true dat. In your neck of the woods a choke and a 180* thermostat are your best friends!!!

 

[byoul]

Yeah maybe I should be waiting for it to warm up a little more, but it does seem to take a long time. What is the best way to test for my accelerator pump to see if gas is being pumped in appropriately. I had one mechanic a while back say that my engine may be bogged down a bit because my secondaries shot gas too quickly, causing a backlog of gas and that can cause a hesitation...That didn't make sense to me. I think my carb needs some readjusting and I should look at my accelerator pump, what is the correct course of action in adjusting carbs and accelerator pumps? Thanks!

 

[74 hatchback]

What kind of carb is it?

 

[byoul]

It's an edelbrock 4 barrel, I'm not sure on the CC I can check tonight for sure, I'm in the library studying (I'm supposed to be studying invertebrate biology...I mostly end up studying the stevesnovasite forums)

 

[74 hatchback]

Im running a 750 eddy on my 454 too. sounds like accelorator pump failing.

 

[USMCNOVA]

Mine was acting the exact same way for the longest time. Usually when it was still cold. I advanced the initial timing and then hooked up a vacum gauge to set the air fuel mixture to get the highest possible reading and now it runs like a scalded cat.

 

[byoul]

USMCNOVA that sounds interesting, how do I go about adjusting initial timing? And what is involved with hooking up a vacuum guage? I guess the first thing I should do based on the advice from the thread is inspect the accelerator pump. 74 hatchback what is it I should be looking for with the accelerator pump, and do you have any adjustment tips?

 

[USMCNOVA]

USMCNOVA that sounds interesting, how do I go about adjusting initial timing? And what is involved with hooking up a vacuum guage? I guess the first thing I should do based on the advice from the thread is inspect the accelerator pump. 74 hatchback what is it I should be looking for with the accelerator pump, and do you have any adjustment tips?

I haven't messed with mine, but I think on the Edelbrock carbs you can adjust the accelerator pump to give you a bigger shot...? Have to look at the manual. Maybe go online to the tech page of the Edelbrock site. To set the timing I disconected the vacuum advance and set the timing with a timing light to about 14 degrees (I was running closer to 8 or 10 before..no where near enough). Then with the vacuum advance hooked back up I adjusted the idle. Once I had it where it needed to be, I connected the vacuum gueage to the port on the carb and adjusted one side (air/fuel mixture screw) to get the highest possible reading. As I was doing this the needle really steadied out when I got the best reading. I then did the same to the other side, and readjusted the idle. Car idles much smoother and runs much better now. Doesn't want to stumble or die. I am no professional so I am probably missing something, but it worked for me.

 

[LeftCoast Carl]

must be that time of year.i'm having the same trouble and suspect that a winter of sitting with old gas has been a contributing factor.
leftcoast carl.

 

[burns]

I haven't messed with mine, but I think on the Edelbrock carbs you can adjust the accelerator pump to give you a bigger shot...?

There should be a rod on the front drivers side of the carb connected to the accelerator pump. There are three holes in the linkage that the accelerator can be adjusted to. Just pull out the small cotter pin and move the rod to a different hole and replace cotter pin. I personally had the same problem with my edelbrock and switched to a dyno tuned custom built holley. Problem is gone and the holley was cheaper than I what I payed for the edelbrock.

 

[66german]

how do I go about adjusting initial timing? And what is involved with hooking up a vacuum guage?

I think there might be the real problem in the first place.

DO NOT just blame it on the carb - first CHECK the timing! You need to properly set your basic timing, mechanical and vacuum advance curve BEFORE working on the fuel side. Please use the "SEARCH" function of this forum to get info on how to set timing. THEN care about the carb - if you still have to...

Regards from overseas,

Boris