carb adjustment - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dmurphy68 · 01-12-2003, 08:10 AM

I need to know what is the best way to tune a carb. I have an elderbrock (aka carter) just wanted to know what rpm you all are running in drive. and what are the two screws in front are for . my carb is a 1405 600 cfm. any help would be great
thanks
Darren

ChevLoRay · 01-12-2003, 08:48 AM

If you don't have the manual that came with it, go to www.edelbrock.com. From their home site, you can navigate around and get to the section that has all kinds of information, from technical stuff to tuning to parts info.

If you have never tuned a carb, I suggest you get that info, first. There are several ways to "adjust" the carb, i.e., using vacuum measurements, rpm's, etc.

The two screws you are referring to are for idle air. They can become a big problem if you damage them. The way they get damaged is by screwing them in, until they bottom-out with sufficient force to cause a groove to be cut at the taper (needle) end. IF that happens, you cannot get them to adjust properly.

As for an idle speed, I believe that you can generally go with an idle speed of 700 RPM's, in drive. That may mean about 750-850 RPM's, as it idles in neutral.....with a warm engine. If the engine is cold, and the choke is engaged, the idle speed will be higher, so wait until the choke is disengaged before adjusting the idle speed, or anything else, for that matter.

So, go to their website and download the info and PRINT a copy for yourself to keep on-hand.

dmurphy68 · 01-12-2003, 08:54 AM

Thanks alot ChevLoRay. the carb is bran new and i have the manual but never looked at it i just like getting helpfull tips on here I love this place the people the company makes me want to

. ok thanks for you info i will get it adjusted and break in the new motor.
thanks
Darren

**Classic Heartbeat** · 01-12-2003, 11:38 AM

I have also heard that you will want to run a fuel pressure regulator with that carberator. From what I have read on these and other boards, Edelbrocks don't like pressures above 4 lbs. and the stock fuel pump puts out 6.5 lbs. The result has been an engine that when you floor the throttle, falls flat on its face. I have one on my BB402 in my Blazer and it does seem sluggish to me, but I havn't done anything to it yet. I know there are several carberator guys on here that could explain this better than I can. WES www.ClassicHeartbeat.com

ChevLoRay · 01-12-2003, 04:59 PM

My truck had a model 1401 Edelbrock, manual choke, performance jetting, when I bought it 3 years ago. Last year (2001), I replaced it with a model 1901, Q-Jet, with divorced choke. I am very happy with the swap. I still have the 1401, and a kit from Edelbrock to overhaul it. It ran so rich that the exhaust gas would bring tears to your eyes to be around it. It was running via an adapter on a stock, cast iron Q-Jet intake. I also changed to an Edelbrock Performer intake. It still ran rich with the 1401. The 1901, well let's just say that it is a much nicer arrangement, now.

dmurphy68 · 01-12-2003, 07:29 PM

yea she does run real rich i just thought it was an adjustment. man this sucks i hope i can get it to stop burning my eyes people must think i am crying all the time lol. thanks ChevLoRay for the info
Darren

kaycee · 01-12-2003, 10:42 PM

I never had a problem with mine until I put a K&N filter on it now it runs rich .I had prob. at first but finally got it tuned in(before the filter).I adjusted the air/ fuel and it is not as bad but still noticeable 2 me.The book help's allso as they mentioned b4

01-12-2003, 08:10 AM	#1
dmurphy68 Registered User Join Date: Nov 2002 Location: Middletown ohio Posts: 1,058	carb adjustment I need to know what is the best way to tune a carb. I have an elderbrock (aka carter) just wanted to know what rpm you all are running in drive. and what are the two screws in front are for . my carb is a 1405 600 cfm. any help would be great thanks Darren

01-12-2003, 08:48 AM	#2
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	If you don't have the manual that came with it, go to www.edelbrock.com. From their home site, you can navigate around and get to the section that has all kinds of information, from technical stuff to tuning to parts info. If you have never tuned a carb, I suggest you get that info, first. There are several ways to "adjust" the carb, i.e., using vacuum measurements, rpm's, etc. The two screws you are referring to are for idle air. They can become a big problem if you damage them. The way they get damaged is by screwing them in, until they bottom-out with sufficient force to cause a groove to be cut at the taper (needle) end. IF that happens, you cannot get them to adjust properly. As for an idle speed, I believe that you can generally go with an idle speed of 700 RPM's, in drive. That may mean about 750-850 RPM's, as it idles in neutral.....with a warm engine. If the engine is cold, and the choke is engaged, the idle speed will be higher, so wait until the choke is disengaged before adjusting the idle speed, or anything else, for that matter. So, go to their website and download the info and PRINT a copy for yourself to keep on-hand. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

01-12-2003, 11:38 AM	#4
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	I have also heard that you will want to run a fuel pressure regulator with that carberator. From what I have read on these and other boards, Edelbrocks don't like pressures above 4 lbs. and the stock fuel pump puts out 6.5 lbs. The result has been an engine that when you floor the throttle, falls flat on its face. I have one on my BB402 in my Blazer and it does seem sluggish to me, but I havn't done anything to it yet. I know there are several carberator guys on here that could explain this better than I can. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys

01-12-2003, 04:59 PM	#5
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Edelbrock comment.... My truck had a model 1401 Edelbrock, manual choke, performance jetting, when I bought it 3 years ago. Last year (2001), I replaced it with a model 1901, Q-Jet, with divorced choke. I am very happy with the swap. I still have the 1401, and a kit from Edelbrock to overhaul it. It ran so rich that the exhaust gas would bring tears to your eyes to be around it. It was running via an adapter on a stock, cast iron Q-Jet intake. I also changed to an Edelbrock Performer intake. It still ran rich with the 1401. The 1901, well let's just say that it is a much nicer arrangement, now. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

01-12-2003, 10:42 PM	#7
kaycee Registered User Join Date: Jan 2000 Location: Wyoming USA Posts: 2,445	I finally got rich 2 I never had a problem with mine until I put a K&N filter on it now it runs rich .I had prob. at first but finally got it tuned in(before the filter).I adjusted the air/ fuel and it is not as bad but still noticeable 2 me.The book help's allso as they mentioned b4 __________________ 2001 Silverado K-1500 2005 FXDWG stage3 69 CHEVY Short/Step 327/4L60 373 posi 63 IMPALA 327

01-12-2003, 08:54 AM	#3
dmurphy68 Registered User Join Date: Nov 2002 Location: Middletown ohio Posts: 1,058	Thanks alot ChevLoRay. the carb is bran new and i have the manual but never looked at it i just like getting helpfull tips on here I love this place the people the company makes me want to . ok thanks for you info i will get it adjusted and break in the new motor. thanks Darren

01-12-2003, 07:29 PM	#6
dmurphy68 Registered User Join Date: Nov 2002 Location: Middletown ohio Posts: 1,058	yea she does run real rich i just thought it was an adjustment. man this sucks i hope i can get it to stop burning my eyes people must think i am crying all the time lol. thanks ChevLoRay for the info Darren



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.