Hey all

I installed the Offy 4bbl intake and a pair of headers on the Volare tonight, i have a 600cfm carb that i'm putting on it (i know its probably too big but it still SHOULD run find as it did on a stock 318 )

Anyways, the carb came with #65 jets from the factory, thinking this is going to be too much for a stock slant i started out at 55, i pulled the primary bowl off and unscrewed the jets, installed the 55's and then installed the bowl with new o-rings on the transfer tube and installed the "blue" re-usable gasket on the bowl.

I put the carb on the engine and started it up, i figured ok its not idleing (normal for putting a carb on a motor) so i got someone to jump in and keep it running, well i got it running but it WILL NOT IDLE!!!! i have the idle screw backed out ALL the way (i can literally take it out) and i have the idle mixture screws turned out so it'll run (like 3 turns) and it idles at 1500 rpm, as soon as i turn in one of the screws a 1/2 turn it'll die

i just dont know how to get this thing idleing right, i installed the 65 jets again and it made no difference. its not running ritch and seems to be missing and "surging" i've checked for vac leaks and have found none

please gimmy some ideas on this!!! the carb ran MINT on a stock 318 with just a 4bbl intake added, now it wont idle worth crap for me will drilling a small (1-3/16ths of a hole in the primary throttle blades help?)

thanks for any help, i need this car for work tommorow!!!!!

Justin

Have you checked the throttle cable & linkage to make sure the valve closes all the way when your foot's off the gas?

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Hey,

Yup, i've even had the throttle cable disconnected and pushed on the linkage to make sure everythings closed, this is really odd... maybe the secondary's are opening? but this wouldnt explain me having the idle screws out 3 turns and when turning even one in 1/2 turn the motor will DIE, it will not idle in gear (great in park or "N" but as soon as it hits a gear it will die instantly.... the timing is at 8* (tried playing with it) and i'm not 100% sure what the vac is but this is starting to get to me

It's possible that it's either vacuum related, or the secondaries are indeed open. I'm not entirely knowlegable with 4 barrel carbs, so I can't be a whole lot of help, but I'd take a look at those two and see what things look like there.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Is this idling on a cold slant with the choke plate wide open? Does this use the automatic choke or divorced choke or even the manual choke model?

Are all the 'ports' on the carb plugged?


mmmmm....tink'r'tunin' the Holley....

my turn's comin' soon I think...

-D.Idiot

Sounds to me like you've got some sorta major vacuum leak, dude. By the way, changing jets will have no effect on the idle circuit, unless the throttle blades are so wide open that it's pulling fuel from the main metering circuit, but the fact that your idle mixture screws are having an effect is telling me that's probably not the case. Holleys are junk (my opinion), but you should be able to get it to idle, at least. Make sure you don't have a major vacuum leak somewhere and report back. Check the adapter to manifold gasket. Also look for a blown power valve.

"DW"

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If it ain't broke, fix it!

Dude, your getting too much air into the engine at idle -- it's most likely vacuum leaks. It's running at 1500 rpm at "idle" because that's where it thinks the throttle's set (with all the air and fuel its getting). It's probably running a little lean too. The fact that you need to have the idle mixture screws all the way out to keep it running, and it's still got a miss, point to this.

I had a similar problem with a quadrajet (on a chevy) and it turned out to be a combination of a leak in the carb base gasket, and the throttle shaft bores were so worn they were passing lots of air.

Check for vacuum leaks. Check the secondaries to make sure they're completely closed. Check the primaries to be sure they're closed all the way and check for play in the shaft.

Do not drill bypass holes in the throttle plates; that'll only make it worse.

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My truck is a Frankenstein creation
Built from the dead carcasses of others
And brought BACK TO LIFE!

hey,

i'll have to check again for gasket leaks, i think i suspect the intake/exhaust gasket... is there any brand of sealent i can buy to put on the gaskets?

thanks
Justin

Hey,

ok i fixed the vac leaks and now i can turn the idle screws IN completely and back the idle rpm adjuster all the way OUT and the thing idles at 1500rpm (this is a electric choke carb with the choke open and not hooked up)

so a new problem has arose

Justin

I know you said the choke's open, but what's the fast idle cam doing (it's up inder the choke stat)? Sometimes they hang up. You do have the fast idle screw backed off, don't you? If all this is ok, I still say a vacuum leak. By the way, is there an echo in here?

"DW"

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If it ain't broke, fix it!

hmmm, an interesting thought about the fast idle cam (i really dont use chokes much) but no i dont have the screw backed off i dont think

i'll have to check it out when i go from the 65 - 55 jets again, its running alittle TOOOO ritch now that the vac leaks are fixed

Justin

Justin, your making way too big of a jet change at a time. When a Holley is jetted right, it takes a 30* change in temperature to need a change of 1 jet size. Your jetting down to 55s is like a drop of 300* in temp. I don't think it gets that cold in Canada.

Cecil

He's just trying to get a baseline, I believe. I've never put a 600 Holley on a /6, but the 390 was using 49-52 primary jets on my /6, if I remember correctly.

"DW"

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If it ain't broke, fix it!

If the idle mixture screws are all the way in and it still runs at idle, I'd say make sure the throttle linkage is not holding the throttle open a little. If that checks out ok, they I'd say that for some reason enough air is making it past the throttle plates to draw fuel from the main fuel circuit. A vacuum leak won't do it with the idle mixture screws all the way closed if nothing else is wrong, as the idle circuit will be incapable of delivering fuel to mix with the leaked air. Likewise, the fact that the idle speed screw is backed all the way out points to air leaking past the throttle plates.
Assuming that the throttle linkage is not holding the throttle partly open, I'd pull the carburetor off the motor and hold it up near a light. Making sure the throttle blades are as closed as they can be, look from the bottom of the carb and see how much light makes it around the throttle plates. If there is a lot, or if one or two show a lot more light than the others, there's the problem. If the secondaries are open slightly, this test will show that too.

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Everyone driving slower than me is a moron. Everyone driving faster than me is an idiot. With all these morons and idiots on the road, I can't get anywhere!

Hey, Cecil i tried the 65's when i got it running right this morning and it was just too ritch, i jetted down to the 55's saying this is a stock slantsix and i did want to baseline it, it runs good with the 55's and i may do more "tinkering" later on.

Yup the throttle was held up, i disconnected the electric choke and yup, the high idle cam was stuck against the screw so i just took the screw out, the 600 runs like a champ, on my 1 wire O2 meter its running about 450mv which is around 14.7ish:1 a/f ratio, i have to make up an actuall 2 wire meter for it but thats later.

Thanks for the help everyone!!!

Justin