Please Help! How do I adjust my Holley Carb Accellerator Pump?!?! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 04-25-2003, 12:34 AM

My friend said if my truck bogs off a dead stop only, my accelerator pump is out of adjustment, he can't get to it till saturday, and I REALLY need to have it adjusted by 2moro. Any ideas on how to do this? My carb is Holley Part # 80460. Thanks!

TIMSPEED · 04-25-2003, 12:38 AM

Also, after I rev it, it'll run rough.
Rev it = One punch TO THE FLOOR rev. (to 3000rpm)
It'll run like it's gonna die after I rev it going all the way to the floor. Please help!

Mike76251 · 04-25-2003, 01:04 AM

This is from Holley.com,
See if it helps.

QUESTION My vehicle has a stumble from a dead stop. What can I do to cure this?

ANSWER The most common cause of a stumble is not having an adequate accelerator pump shot. The first thing to do is to look at the discharge nozzle and make sure you are getting a good strong pump shot. If not then you need to inspect the pump diaphram for a hole or tear. You will also need to make sure that the pump passage is clear from any trash or debris. First you will need to check the adjustment on the pump. To do this you will open the throttle all the way (WOT). Push the pump arm lever down and then adjust the pump override spring to obtain .015" clearance between the pump arm and lever. If you are having a stumble and no black smoke out the tailpipe then you will need to increase the shooter size. If it stumbles and you are getting black smoke from the tailpipe then it will be nessasary to decrease the shooter size.

QUESTION I have a vacuum secondary carburetor that bogs when the secondaries come in. What will cause this?

ANSWER Bogging and hesitation are caused by the secondaries coming in to quickly. You can install a heavier secondary spring and this will prevent the secondary from coming in to soon. If the engine is sluggish in response at full throttle then the secondaries may not be opening soon enough. You will then need to go to a lighter spring.

TIMSPEED · 04-25-2003, 01:06 AM

Right, my friend's dad said my accelerator pump is out of adjustment, so I tried to adjust that spring..but if I'm to adjust it so the arm is only .015" away from the lever..then I'm gonna have to CUT the spring. But my spring isn't adjusted by a screw, it's adjusted by a nut...so..I mean, it makes no sense to me...shouldn't this carb be a bolt-on and go thing???

Mike76251 · 04-25-2003, 01:23 AM

Every Holley I have bought in the last 10 years was a bolt-and-go deal.
Is this carb new out of the box?
Has anyone been tuning it?

It looks to be one of Holley's "universal" carbs.
If this thing is new out of the box then it may take some tuning.

They tend to run a little rich out of the box so you don't fry your motor with them.

The carbs I have bought .... the 'Street Avengers" series all ran great out of the box.
They cost a little more but you don't have to tune them.

TIMSPEED · 04-25-2003, 01:26 AM

Quote:

Originally posted by Mike76251
Every Holley I have bought in the last 10 years was a bolt-and-go deal.
Is this carb new out of the box?
Has anyone been tuning it?

It looks to be one of Holley's "universal" carbs.
If this thing is new out of the box then it may take some tuning.

They tend to run a little rich out of the box so you don't fry your motor with them.

The carbs I have bought .... the 'Street Avengers" series all ran great out of the box.
They cost a little more but you don't have to tune them.

No one's tuned it yet...and I had to get this carb, for smog purposes..I'll prolly have to increase my shooter size.

Mike76251 · 04-25-2003, 01:38 AM

It does sound like you need to change shooters.
You are either going lean or rich off idle.
These are two "stage" carbs more or less with one stage handling idle and another handling anything else.

I would go rich with the shooter and see if that helps.

Sorry I can't help more but with this storm I have gotten ten disconnects just trying to answer your questions.

TIMSPEED · 04-25-2003, 02:26 AM

ok, I set the accelerator pump spring..but still..it will never idle the same way twice.
I can get it idling all smooth and nice, then as soon as I mash the throttle, it idles differently (like it wants to die)
I really hate carbs! LOL I'm a Fuel Injection guy, I tune chips to make it idle smoother, not fiddle with screws and crap!

Mike76251 · 04-25-2003, 02:36 AM

I hope you didn't tighten the four screws holding the carb down too much.
That can cause a linkage bind.

Something else that can cause it is a thick carb gasket.
I see people put a new carb on and use a super thick gasket on it and crank down the screws. That is the best way to warp the carb forever. It takes a new carb to fix it.

TIMSPEED · 04-25-2003, 03:28 AM

Hmm..come to think of it, I DO have a thick gasket in there..but why would that be my problem? I have a half inch thick gasket (two quarter inch thick gaskets combined) under the carb...the mechanic that put the carb on last year said I needed the thicker gasket and it would prolly give me more torque...dude, if that's my problem, I'll pull that shiz off ASAP!

Mike76251 · 04-25-2003, 05:47 AM

I will tell you why that thick gasket is a problem,

Now...let me state that this is not my words but Holley's;

Gaskets are softer than the pot metal (zinc) baseplate of your carb.
These (or any) carbs when bolted down have all the pressure on the locations where the bolts are.
In a Holley this is on the four corners.
When you have something soft like a gasket under the carb and put all the downward pressure on the corners with the bolts, the gasket compresses much more directly under the bolts than it does anywhere else.
This warps the carb's baseplate toward each of the corners.
This results in bound-up linkage and a wasted carb.
Holley gets a lot of them back because of this.
If you will look in the instructions that came with your carb you will this problem listed and warned against.
It was in the instructions for the last few Holleys I bought.

They warn to only use the thin gasket that they give you in the box. That paper one.

If it is more torque you are after, get a Aluminum 4-hole spacer.
At least the mechanic was half right. Spacers (sometimes) give you more torque lower in the RPM band. Open hole spacers tend to move the powerband up.

If this thing has been on there 6 months then it is probably too late.
If you send it back to Holley they will not honor a warranty claim 'cause they have been down this road many many times before.
Let me know how it turns out when you get the right gasket under there. You might get lucky.

04-25-2003, 12:34 AM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Please Help! How do I adjust my Holley Carb Accellerator Pump?!?! My friend said if my truck bogs off a dead stop only, my accelerator pump is out of adjustment, he can't get to it till saturday, and I REALLY need to have it adjusted by 2moro. Any ideas on how to do this? My carb is Holley Part # 80460. Thanks! __________________ I have a few cars... See Them Here

04-25-2003, 12:38 AM	#2
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Also, after I rev it, it'll run rough. Rev it = One punch TO THE FLOOR rev. (to 3000rpm) It'll run like it's gonna die after I rev it going all the way to the floor. Please help! __________________ I have a few cars... See Them Here

04-25-2003, 01:06 AM	#4
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Right, my friend's dad said my accelerator pump is out of adjustment, so I tried to adjust that spring..but if I'm to adjust it so the arm is only .015" away from the lever..then I'm gonna have to CUT the spring. But my spring isn't adjusted by a screw, it's adjusted by a nut...so..I mean, it makes no sense to me...shouldn't this carb be a bolt-on and go thing??? __________________ I have a few cars... See Them Here

04-25-2003, 02:26 AM	#8
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	ok, I set the accelerator pump spring..but still..it will never idle the same way twice. I can get it idling all smooth and nice, then as soon as I mash the throttle, it idles differently (like it wants to die) I really hate carbs! LOL I'm a Fuel Injection guy, I tune chips to make it idle smoother, not fiddle with screws and crap! __________________ I have a few cars... See Them Here

04-25-2003, 03:28 AM	#10
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Hmm..come to think of it, I DO have a thick gasket in there..but why would that be my problem? I have a half inch thick gasket (two quarter inch thick gaskets combined) under the carb...the mechanic that put the carb on last year said I needed the thicker gasket and it would prolly give me more torque...dude, if that's my problem, I'll pull that shiz off ASAP! __________________ I have a few cars... See Them Here

04-25-2003, 01:04 AM	#3
Mike76251 Senior Member Join Date: Mar 2003 Posts: 2,499	This is from Holley.com, See if it helps. QUESTION My vehicle has a stumble from a dead stop. What can I do to cure this? ANSWER The most common cause of a stumble is not having an adequate accelerator pump shot. The first thing to do is to look at the discharge nozzle and make sure you are getting a good strong pump shot. If not then you need to inspect the pump diaphram for a hole or tear. You will also need to make sure that the pump passage is clear from any trash or debris. First you will need to check the adjustment on the pump. To do this you will open the throttle all the way (WOT). Push the pump arm lever down and then adjust the pump override spring to obtain .015" clearance between the pump arm and lever. If you are having a stumble and no black smoke out the tailpipe then you will need to increase the shooter size. If it stumbles and you are getting black smoke from the tailpipe then it will be nessasary to decrease the shooter size. QUESTION I have a vacuum secondary carburetor that bogs when the secondaries come in. What will cause this? ANSWER Bogging and hesitation are caused by the secondaries coming in to quickly. You can install a heavier secondary spring and this will prevent the secondary from coming in to soon. If the engine is sluggish in response at full throttle then the secondaries may not be opening soon enough. You will then need to go to a lighter spring.

04-25-2003, 01:23 AM	#5
Mike76251 Senior Member Join Date: Mar 2003 Posts: 2,499	Every Holley I have bought in the last 10 years was a bolt-and-go deal. Is this carb new out of the box? Has anyone been tuning it? It looks to be one of Holley's "universal" carbs. If this thing is new out of the box then it may take some tuning. They tend to run a little rich out of the box so you don't fry your motor with them. The carbs I have bought .... the 'Street Avengers" series all ran great out of the box. They cost a little more but you don't have to tune them.

04-25-2003, 01:38 AM	#7
Mike76251 Senior Member Join Date: Mar 2003 Posts: 2,499	It does sound like you need to change shooters. You are either going lean or rich off idle. These are two "stage" carbs more or less with one stage handling idle and another handling anything else. I would go rich with the shooter and see if that helps. Sorry I can't help more but with this storm I have gotten ten disconnects just trying to answer your questions.

04-25-2003, 02:36 AM	#9
Mike76251 Senior Member Join Date: Mar 2003 Posts: 2,499	I hope you didn't tighten the four screws holding the carb down too much. That can cause a linkage bind. Something else that can cause it is a thick carb gasket. I see people put a new carb on and use a super thick gasket on it and crank down the screws. That is the best way to warp the carb forever. It takes a new carb to fix it.

04-25-2003, 05:47 AM	#11
Mike76251 Senior Member Join Date: Mar 2003 Posts: 2,499	I will tell you why that thick gasket is a problem, Now...let me state that this is not my words but Holley's; Gaskets are softer than the pot metal (zinc) baseplate of your carb. These (or any) carbs when bolted down have all the pressure on the locations where the bolts are. In a Holley this is on the four corners. When you have something soft like a gasket under the carb and put all the downward pressure on the corners with the bolts, the gasket compresses much more directly under the bolts than it does anywhere else. This warps the carb's baseplate toward each of the corners. This results in bound-up linkage and a wasted carb. Holley gets a lot of them back because of this. If you will look in the instructions that came with your carb you will this problem listed and warned against. It was in the instructions for the last few Holleys I bought. They warn to only use the thin gasket that they give you in the box. That paper one. If it is more torque you are after, get a Aluminum 4-hole spacer. At least the mechanic was half right. Spacers (sometimes) give you more torque lower in the RPM band. Open hole spacers tend to move the powerband up. If this thing has been on there 6 months then it is probably too late. If you send it back to Holley they will not honor a warranty claim 'cause they have been down this road many many times before. Let me know how it turns out when you get the right gasket under there. You might get lucky.



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