holley 600 help

[mean350]

how do you set the idling on a holley 600cfm carb?:confused: thanks a bunch

[SWIGIN]

with the idle screw on the left side.....no joke

if you mean the air screws what i do is turn them in slowly till the motor starts to stumble then go out till it stumbles and put it right in the middle

[mean350]

thers only 1 screw for the idle then? i though it was the screws that are on each side of the carb,.

[SWIGIN]

those are the air screws

[SWIGIN]

http://www.holley.com/

this will help

[mean350]

thanks!!!!!!!

[MO dx]

If you were closer thats what my specialty setting up carbs on hotrods.

[bondoboy]

Gently turn both idle mixture screws in until they bottom out. Back each one out 1and 1/2 turns. Hook a vacuum gauge to a full manifold vacuum source. Start the engine. Back each screw out the same amount until you get the highest vacuum reading. If you go too far, the vacuum will drop and you will have to turn them in a little bit. Then, set your idle speed with the screw on the throttle linkage.

[mean350]

which vacuum? i cant leave it running it revs so high

[bondoboy]

A full vacuum port would be in the baseplate of the carb, like the port your modulator line runs to for an auto transmission. Is your whole problem the high idle? A vacuum leak in the carb to intake gasket will make it run too fast. Is the fast idle turning off when the engine warms up? Do you have an electric choke? Is your idle speed screw turned in too far? Your idle speed screw is on the linkade near where the throttle cable hooks up. Screwing it in simply opens the throttle. Is your throttle returning to the closed position? Usually the stock throttle cable bracket will not put the proper tension on the spring and engine vacuum will crack the throttle. If this is the case, holley makes a bracket. Let me know if you need more help.

[mean350]

there is no port in the baseplate of the carb. theer is just 2 of them on the side. the idle screw is turned the whole way out and it is not sticking anywhgere. its a manual choke. the throttle is returning fine.i dikdnt look at it whikle the engine is running cause the idle is so high. when i firdst fire it up it aint bad then it revs like crazy.

[bondoboy]

Is your carb a single fuel line vacuum secondary? What model number is stamped on the choke tower? Is it 1850? You should have an 11/32 vacuum port on the base for the PCV hose and there should be a small port at the front of the carb on the passenger side. If you have the choke off and tap the throttle, do the rpm's come down? Your fast idle may be set too high. I would almost bet it's the fast idle or you have a vacuum leak. What kind of vehicle is this on? Is the carb new? Did you just install it?

[mean350]

no its not an 1850. its like 6... and no the rpms does not come down when i hit he gas. how do i adjust the fast idle?

[mean350]

its a 6520

[cr480r]

how do i adjust the fast idle?

The fast idle is usually part of the choke linkage... shouldnt matter unless the chock is engaged. It sounds to me like a your throttle is hung open(most likely improper cable or bracket), or your curb-idle is just set way too high. If you look at the lingage you will see the curb-idle adjuster... then peek down inside the carb and look to see if the throttle blades are closing. the secondaries can hang open too... After you get it to idle down to a reasonable level... then follow the methods described by bondoboy for adjusting the idle-mixture adjustment screws... That is how I do them...and probably the easiest for those that havent developed a feel for it.

[mean350]

ok thanks im gonna check that out. can i just unhook my throttle and see if it still revs high?

[bondoboy]

Is that an old carburetor? I can't find any info on it. Has it been rebuilt? If you have the choke off, and you tap the gas, the fast idle should kick off. I'm thinking it's a vacuum leak somewhere.

EDIT:

I just looked and found that it's a 2 barrel. I was thinking 4 barrel. What kind of vehicle is this on? I don't know much about this model. If it was a 4 barrel, I could help you.

[cr480r]

the throttle is returning fine.i dikdnt look at it whikle the engine is running cause the idle is so high. when i firdst fire it up it aint bad then it revs like crazy.

Is there a return spring on the linkage? Does the throttle lever rest against the idle speed adjuster? Check to be the sure the secondaries are closed too... They have an idle circuit of their own... Its not likely to have a problem with the secondary linkage...but it does happen...

[bondoboy]

Is there a return spring on the linkage? Does the throttle lever rest against the idle speed adjuster? Check to be the sure the secondaries are closed too... They have an idle circuit of their own... Its not likely to have a problem with the secondary linkage...but it does happen...

This is a 2 barrel carb. It looks like it is something off of a newer vehicle. It is not made like the classic holley with the bowls on the front and rear.

[cr480r]

I'm thinking it's a vacuum leak somewhere.

Very likely possibility if everything else checks out.. Are all your vaccum ports plugged? PCV and Power brakes hooked up? Transmission modulator? Vaccum advance?(should be to a ported vaccum source, not full vaccum)

[cr480r]

This is a 2 barrel carb. It looks like it is something off of a newer vehicle. It is not made like the classic holley with the bowls on the front and rear.

thats what a quick search showed me as well... I thought this was on a edelbrock torker manifold??????

[mean350]

no its a 4 bbl holley 600cfm. its on a chevy 307 w a torker 2 intake.

[mean350]

Is there a return spring on the linkage? Does the throttle lever rest against the idle speed adjuster? Check to be the sure the secondaries are closed too... They have an idle circuit of their own... Its not likely to have a problem with the secondary linkage...but it does happen...


yes ther is a spring. the throttle lever does not rest aganst the idle screw.

[bondoboy]

6520 is not the number for a 4 barrel. If all of your vacuum ports are capped and in use, you probably have a vacuum leak under the carb. Change the carb to intake gasket and see what happens. It only takes 10 minutes and 7 dollars. Don't overtighten the carburetor or you'll warp the base and it will never seal.

[mean350]

the list number on my carb is 6520. the intake gasket is brand new too.

[bondoboy]

Is the carb new? It would be extreme, but did a throttle plate come loose? It has happened. Without seeing the vehicle, I can't help too much.

[mean350]

i think tis the fast idle. im gonna pull the carb off tomorrow.

[mean350]

i still cant figure it out. the fast idkle is fine but the dang thing will not close cause the secondaries are suck open a little bit which holds the primaries open too. it seems like the secondaries are too big for the carb....idk thoungh

[SWIGIN]

http://cgi.ebay.com/ebaymotors/Holley-600-CFM-1850-S-Remanufactured_W0QQcmdZViewItemQQcategoryZ33550QQi hZ019QQitemZ290100197203QQrdZ1

[mean350]

im trying to find a used edlebrock 600 for it.

[bondoboy]

Are the secondaries stuck open even when the engine is not running? If this is a vacuum secondary carb, there is a secondary throttle plate stop screw that may need adjustment. You have to take the carb off. On the bottom of the baseplate below the secondary diaphragm, there is a small screw that adjusts how far the secondaries close. It may be in too far. Holley recommends that it is adjusted in until it touches the secondary linkage, then a partial turn more, but I don't remember how much. I will check. Again, is this carb new or used? Maybe someone else turned this screw?

[mean350]

i see the screw and it not even tounching anything. it is used. its a vacuum secondarie. not a double pumper or anything.

[mean350]

i took it off and put the stock intake and 2bbl carb back on. i got tired of messing w it. thanks for all the help