Help tuning a Edelbrock 600 Carb

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Engine: 1971 Chevy 355<BR>Cam: Crane Energizer 2200-5200, 274/274 ADV DUR, 218/218 DUR, 106 Slope, .450/.450 lift<BR>Carb: Edelbrock Performer 600 w/ electric choke<BR>Intake: Weiand Stealth<BR>Ignition: Stock<BR>Headers: Hedman<BR>Heads: Stock (Surfaced & Cleaned)<P>Hi everyone, I have got about 400 miles on my new engine and I have been having problems tuning the carb. I think I have the choke set right (almost closed cold, open hot) but I am having a idle problem. I am trying to get it to stay around 1700rpm (fast idle) and about 900 when hot. The problem I am having is that sometimes it stays that way and other times I get home after a 30 mile drive and it idles at 2000 rpm??!! Also sometimes the car won't idle by itself and need to feather the gas to keep it going (until it warms up). Also sometimes if I kick it off fast idle it will just quit.<P>I have been messing with the fast idle screw as well as the other idle screw. Can someone explain the differences between these and also give me some advice. I am from Minnesota and it is getting cooler is that going to make it harder??<P>Thanks! <P>-Bill

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Vroom-vroom!! What's intake manifold<BR>vacuum when the thing DOES idle at 900?<BR>That looks like a lot of camshaft! Do<BR>power brakes work reliably? EVERYTHING ELSE IN THE ENGINE HAS TO BE DIALED IN<BR>DEAD NUTS BEFORE YOU MESS WITH CARB!<BR>Did you use a degree wheel to dial-in<BR>camshaft? Does the vacuum gauge flutter<BR>when you hook it up? A slowly varying reading might be ok, but a high-speed <BR>flutter means trouble other than the carb. Valve adjust/pre-load OK?<BR>Does this carb have electric choke? Where<BR>did you connect the wire? Power with key<BR>on or did you wire through oil pressure<BR>switch? Running PCV? Maybe some kind of<BR>preheat system is in order for Minnesota!<BR>Racers hate them, but a nice Thermal Air<BR>Cleaner might be good. Got to have vacuum<BR>to run it, though. Take it off for summer! Engine have intake deposits? These little deposits act like sponges right when cylinders need fuel the most. I use BG products to remove carbon.<BR>Is an Edelbrock 600 Rochester based? In<BR>other words does it look like an old Chevy carb or something else? Good Luck<BR>Don Kenyon ASE Certified Master Tech, L-1,CA EA Smog License<BR>

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The Edelbrock carburator is a Carter design.<BR>The old Carter AFB / AVS design was updated and retuned as the new Carter 9000 series and Edelbrock carburators. It is now fully emissions legal with all the right ports.

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The fast idle will control the cold idle, and will drop in steps as the engine warms. By the way, the choke should be closed all the way, regardless of the outside temp, when the engine is overnight cold. Initial fast idle should be set at about 2200 rpm. It can be adjusted up or down as needed from this point. Your warm idle may be addressed by some experiernce on my part. On some carbs the throttle shaft is too far off center, and in combination with a weak throttle return spring, it will cause incoming air to partially open the throttle. You can confirm this by having a friend watch the throttle when this condition occurs. If, when you kill the ignition, the throttle closes further, that is your problem. My apologies on this late reply: I just found this forum.

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TroubleInParadise:<BR>Engine: 1971 Chevy 355<BR>Cam: Crane Energizer 2200-5200, 274/274 ADV DUR, 218/218 DUR, 106 Slope, .450/.450 lift<BR>Carb: Edelbrock Performer 600 w/ electric choke<BR>Intake: Weiand Stealth<BR>Ignition: Stock<BR>Headers: Hedman<BR>Heads: Stock (Surfaced & Cleaned)<P><HR></BLOCKQUOTE><P>Hey there. I had the exact same cam in my 77 350 with ZZ4 heads. My Edelbrock worked great with a Crane 272 with iron heads for 8 years. The carb simply could not be dialed in for the new combo. After trying a few Q-jets, I got a used Holley 1850 and the thing runs perfectly. I think the Edelbrock might have had the idle transfer slots exposed. This is due to the excessive throttle opening just to get the thing to idle with that big cam. Just my two cents....