Other than the mixture screws not seeming to respond, how does it run?
holley 600 won't adjust
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Joined: Aug 2002
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From: Chattanooga US
holley 600 won't adjust
Hey guys;
I've got a '73 bronco with a stock 302/c4. I just recently installed an edelbrock performer intake w/a new holley 600 vac sec. I'm having a problem with the idle mixture screws. I can turn them all the way in to the point where the truck should die but it never changes the idle at all. At first guess I assumed that it had to be a vacuum leak, but I've looked everywhere and found none. The lowest I can make it idle is 650-700 rpm's. I've run propane all over this engine trying to find a leak and there don't seem to be any. Am I missing something? Ideas?
Greg
I've got a '73 bronco with a stock 302/c4. I just recently installed an edelbrock performer intake w/a new holley 600 vac sec. I'm having a problem with the idle mixture screws. I can turn them all the way in to the point where the truck should die but it never changes the idle at all. At first guess I assumed that it had to be a vacuum leak, but I've looked everywhere and found none. The lowest I can make it idle is 650-700 rpm's. I've run propane all over this engine trying to find a leak and there don't seem to be any. Am I missing something? Ideas?
Greg
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From: Chattanooga US
You'd be correct on the 550 part, but I can't make it go any lower(not that I'd want to) but shouldn't it have the ability to be adjusted to the point that the engine dies? But to update I FINALLY found a vacuum leak around the secondary diaphram on the carb, that and I have 6 degrees of slack in the timing chain. At 10 deg. of initial timing the engine pulls 13 in of vacuum.
I'll change the timing chain this weekend.
Greg
I'll change the timing chain this weekend.
Greg
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Joined: May 2003
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From: south louisiana
If the idle mixture screws don't affect the idle speed, you have the throttle blades open too far, uncovering the transfer slots, putting the carb into the transition stage. Close the throttle blades all the way, then try the screws again. If they still don't work, you may have trash in their passages.
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From: Chattanooga US
The throttle blades are completely closed, to the point that the curb idle adjusting screw is nowhere near touching the throttle lever. I'll be replacing this carb tomorrow.
Greg
Greg
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From: youngstown ohio
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From: Manitoba Canada
Ok.. having been through this myself, I'll shed some light on things. First thing to check is the secondary throttle stop. (are the secondaries fully closed). Second, check the inlet needle height. you should have fuel ALMOST ready to trickle out of the site holes. Third, (and this was my problem) remove the main meetering block and make SURE that you have both idle air bleeds. Not having them will cause a rich running situation at idle. If that's the problem, return the carb to the place of purchase and get another. Don't worry, those carbs are easy to work on. they were designed to be quick for racers to service and that makes them easy for us to figure out. Also, if you can find it... get the book on tuning holly carbs. It will really open your eyes to what can be done with those chunks of aluminum that we cal carburetors.
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From: Eureka, KS
I've had tons of problems like this with Holley carbs. Some guys just "get" Holley's and some don't I think. I've just went with Edelbrock carbs the last 2 I've replaced. Could never keep the Holleys tuned, one day it was great and the next it needed adjusting.
Holleys make such good power but seem so hard to run and keep running right on a daily driver. Edelbrocks are nice because you usually just bolt them on, adjust the idle and go.
You Holley guys don't yell at me, just telling my experience.
I'd sure run one on a race motor.
Holleys make such good power but seem so hard to run and keep running right on a daily driver. Edelbrocks are nice because you usually just bolt them on, adjust the idle and go.
You Holley guys don't yell at me, just telling my experience.
I'd sure run one on a race motor.
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Joined: Jun 2005
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From: Manitoba Canada
Wierd... I have had mine for going on three years now, and other than my issue with the idle air bleeds, I have yet to have a problem. Also dropped my fuel consumption too! Not braggin, just passing on one of the good stories. I'm sure that for every good experience there are twice as many bad ones for each manufacturer. Whatever ones choice is, so long as they are happy in the end is what truely counts.
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From: Chattanooga US
Finally found the problem.....The metering block on my "professionally rebuilt" holley is full of garbage. This carb was supposed to be spec built with #63 primary jets ( there are corroded #66's in it) power valve protection (not there either) and be re-dyed (it was painted, of course all that came off when I tore it down). I bought another off the shelf 1850 and it works perfectly. The only carbs I've ever run are holleys, I wanted this one done by a pro, so it would be plug and play. Thanks to everyone who helped out.
I think I'll keep the new carb and throw this one through someones window
Greg
I think I'll keep the new carb and throw this one through someones window
Greg