Edelbrock Carb Tuning
Thread Starter
Burning Brakes
Joined: Mar 2001
Posts: 1,211
Likes: 5
From: Nashville TN
Edelbrock Carb Tuning
Any members out there running an Edelbrock Performer carb (750 CFM) ? Curious to know how far you deviated from stock jetting on the unit. Am experinceing some funky intermittent driveability issues and am looking for some help. After periods of light cruise, you engage is a run at WOT and I get all kinds of what looks like soot out of the exhaust. Once that car cleans itself out its fine for WOT runs. It doesn't do it all the time. Do I have a sticking power piston ? wrong jetting ? something else I am over looking ?
Thanks
Thanks
Team Owner
Joined: Jun 2001
Posts: 43,136
Likes: 155
From: Thomson Georgia
Re: Edelbrock Carb Tuning (dman535)
Check out my post on carb bogs on acceleration......... lars and others gave some great answers
Carb is bogging under hard acceleration and black carbon out of tail pipes
Carb is bogging under hard acceleration and black carbon out of tail pipes
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: Edelbrock Carb Tuning (dman535)
You can download the manual from their web site. I had the 750 Edl. performance model for over ten years. One loss of vacuum the spring lifts the rod. so your at max rich (black smoke) So you need to buy the spring kit and maybe go to a lighter spring. This will cause the rod to lift slower and delay the max rich.
Out of the box I found my 750 to be to rich even on my single plane 355 ci. So anyway jets are cheaper than rods. They are easy to change.
Out of the box I found my 750 to be to rich even on my single plane 355 ci. So anyway jets are cheaper than rods. They are easy to change.
Racer
Joined: Oct 2001
Posts: 271
Likes: 0
From: St Louis MO
Re: Edelbrock Carb Tuning (dman535)
Do the simple stuff first like checking for vacuum leaks and choke setting. Also recheck the idle air screws using the edelbrock procedure. I've seen them run rich at idle and low load with the standard 2 1/2 turns out. BTW, how old is the carb?
Gary
Gary
Thread Starter
Burning Brakes
Joined: Mar 2001
Posts: 1,211
Likes: 5
From: Nashville TN
Re: Edelbrock Carb Tuning (Garys '68)
Carb was new this summer. I have had it open a few times trying different jet/needle combinations. What I originally thought was a lean surge ended up being a faulty distributor. The HEI was rebuilt and now its time to tackle the carb. It will on rare occasion backfire and almost sound like its spitting, like a boster was plugged or something like that and it wasn't getting the right amoung of fuel. Car is pulling good vaccum and I can't find any leaks.
Le Mans Master
Joined: Feb 1999
Posts: 6,807
Likes: 0
From: Hoosier
Cruise-In III Veteran
Re: Edelbrock Carb Tuning (dman535)
I may be way off base..but here's a thought. I relate this because my 600cfm 1406 was not set up correctly at first.
Check to make sure the throttles all open fully when you mash the pedal. The back is vacuum activated and if the throttle blades aren't fully open the carb can't react like it should to the signal, throwing the mixture off.
Check to make sure the throttles all open fully when you mash the pedal. The back is vacuum activated and if the throttle blades aren't fully open the carb can't react like it should to the signal, throwing the mixture off.
