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Discussion Starter · #1 ·
Hello. I have a new Holley 750 on my 434 stroker in my Nova. I noticed that the exhaust smells rich or at least richer than it used to. This is at idle and I see that the adjustment screw on the passenger side front float bowl can be screwed in all the way with no noticeable change. The drivers side is like most I have seen, screw it in and you can hear and feel the difference and I haven't done so but feel sure screwing in in all the way would shut the motor down.

I have it set at 1 1/2 turns out and that seems like the point where the idle is highest and further out makes no discernable difference.

But the car runs great, I can stomp it to the floor instantly any time at a dead stop and it just launches hard, tosses the ash tray into the front seat, and can almost give you tunnel vision from the first gear acceleration g forces.

I know, you say "so what's the problem?". I always thought running as lean as possible short of cooking it, was the best way to go in general. And I have had other Holleys that when you screwed in either of the idle mixture screws the engine choked down some. All the way if you persisted.

Anybody know what would cause the "problem" with the passenger side adjuster not "adjusting really" ? And either way, do the screws have any performance effect when I'm on the gas? Thanks very much.. Gary
 

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I'm no expert, but I've found that being fat at an idle isn't a problem. You should feel a difference in both idle screws though. Have you looked at the manual of your carb? Should be pretty straight foreword. Holley's have been hard for me to fine tune from idle to full RPM, but full RPM is all the matters. Right ?
 

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Hey Gary
How ya been. First thing I would do is take the air cleaner off and look down the the carb throat while its running. Be careful.
If you can see gas trickling down the bleeders front or back that would be a high float level which would need to be lowered slightly. Sometimes things change from level or dirt got under the needle and seat which is easy fix. Let me know what you find and we can go from here.
 

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Discussion Starter · #4 ·
I'm no expert, but I've found that being fat at an idle isn't a problem. You should feel a difference in both idle screws though. Have you looked at the manual of your carb? Should be pretty straight foreword. Holley's have been hard for me to fine tune from idle to full RPM, but full RPM is all the matters. Right ?
Ya it could be worse, it does fine and is very drivable in traffic. Even 90 degree days sitting in stop and go traffic don't rattle it a bit, the thermostatically controlled electric fan sees to that. But man I pulled into a car wash bay and the fumes were pretty bad closed in like that.
 

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Discussion Starter · #5 ·
Hey Gary
How ya been. First thing I would do is take the air cleaner off and look down the the carb throat while its running. Be careful.
If you can see gas trickling down the bleeders front or back that would be a high float level which would need to be lowered slightly. Sometimes things change from level or dirt got under the needle and seat which is easy fix. Let me know what you find and we can go from here.
I appreciate this very much Mario. I'll do that tomorrow and see what I got, and it has float level windows on all four corners of the carb, and I will look down the carb as well. I'll let ya know what I found sir, and again thanks!
 

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I appreciate this very much Mario. I'll do that tomorrow and see what I got, and it has float level windows on all four corners of the carb, and I will look down the carb as well. I'll let ya know what I found sir, and again thanks!
Maybe post a pic of the carb too so I can see what you're working with. It's funny but that just happened to my truck recently. Was fine after install for a couple of weeks. Then it started running rich and when I looked in I saw gas trickling down the bleeders on the secondary side. Made an adjustment but it wouldn't help it. Had to unscrew the needle valve assembly out and blow air through it. Put it back and all is fine. Drove it last night in fact and it ran beautiful. This may or may not be your problem. But you can bet that if one side air mix doesn't work then either gas is entering that area involved or you may have a vacuum leak. Also never split a vacuum line to do two functions off the carb. I had that cause a bleed down too once on a Holley carb. Found out the hard way by buying a new carb and having the same bleed down on the new carb. Live and learn.
Let me know what you see at an idle.
 

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Discussion Starter · #7 ·
I appreciate this very much Mario. I'll do that tomorrow and see what I got, and it has float level windows on all four corners of the carb, and I will look down the carb as well. I'll let ya know what I found sir, and again thanks!
Well sir I guess the problem was a small vacuum leak. On the passenger side of the carb up on the front float bowl is a vacuum port. The rubber plug had a crack in it nearly all the way around, and this is the same side the idle circuit adjusting screw that didn't work is on.

After replacing the little plug the adjusting screws both work equally and as intended! I did see that as well, even when the car is warmed up the choke is only 3/4 open at idle. Just touch the throttle at all and it snaps open. But it remains at 3/4 open at all times idling after its warmed up. I have to think its normal. Still I leaned the choke as far as I could and then re tightened the three screws, but the choke didn't lean any. When cold, one full kick to the floor will start the car instantly and it comes to lumpy fast idle. I watched the electric choke open as it warmed up and fully warmed up its at 3/4 open.

With the new adjustment I have now on the carb I was able to smooth and even things out nicely. Thanks Mario and every body for the help, I should have noticed it my self.
 

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Doesn't look right to me it should pull all the way open, if I remember it should have the element coil up against a pin in the housing or hooked on to it...just isn't right...some thing in the housing is off..or you are getting power that is cutting off...check voltage at the terminals...when you turn the housing to adjust is the choke butterfly moving with it...if not its not hooked to the heating element correctly...it is opening with the throttle because there is a piston behind it that pulls it open using vacuum.
 

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The choke should be fully open once warmed up. Since it's electric, it's not activated by engine temperature, but by 12v. power. Even if the engine was never started, power applied when the key is on will eventually open it fully, if it's adjusted properly, and throttle is slightly opened to allow full travel.
Turn the key on without starting the car when it's cool out. Then prop the throttle partially open and watch the choke plate. After maybe 2-3 minutes it should have moved to full open with the throttle partially open. If it doesn't, loosen the 3 screws and carefully move the housing until the choke plate fully opens, but not further! Be sure to keep the throttle partially open while doing this, as it will not allow the choke to fully open if it's in the idle position.
 

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Hey guys sorry I'm late on this. If the throttle does not open slightly when the engine is warmed up the fast idle cam will not drop one being the fast idle and two allow the choke to fully open cause the choke flap is connected to it. The choke spring needs to be somewhere on the scale, front or back. and yes the black ground wire is usually grounded to the choke housing. I guess it doesn't matter but as long as it has a good ground somewhere. The 12 volts although usually overlooked, should come from an oil pressure pass through shut down switch. GM used this oil pressure sender to insure the electric choke did not get 12volts to the choke unless the motor is running. This way you won't get incorrect choke settings on a cold engine.
My ten cents again. :)
 

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Discussion Starter · #12 · (Edited)
Ok, Here is what I have now. I first went out and set the choke with the engine stone cold. I did this by lightly but positively seating the choke flap to the carb. Now the next part I thought was very cool, and I sound just like a dumb kid saying this, but as you know that's pretty much my description. I never had an electric choke on any of my hot rods always manual. So watching the choke open with just the key on was a real joy! The linkage needed a touch of WD-40 but I enjoyed it so much that I waited an hour just to watch it open again! I'm seeking help .

The ground wire is grounded to the intake manifold under one of its bolts. The choke fully opened with just the key on I held the throttle partly open, After starting, and warming up a couple minutes it opened almost all the way at idle but not quite. But beyond 3/4 open as before. Touch the throttle and its open.

Think I got it? I haven't driven it yet.
 

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If you put on a pipe tee fitting you can add this oil pressure choke shut off switch. The choke will only get juice or ground, whichever you choose to pass thru as a circuit, when the motor runs only. So you leave the key on and it won't send juice to the choke till the motor starts giving you accurate choke settings. All the major auto aftermarket make this switch so you don't need to find this manufacturer.
 

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