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Idle issue
https://slantsix.org/forum/viewtopic.php?t=52754		 Page 1 of 1
Author:  jhdeval [ Tue Jul 16, 2013 6:36 pm ]
Post subject:  Idle issue
The car is running great but it won't idle well. I have tried leaning out the carb to no avail. I have tried adjusting the fast and curb idle. Fast idle is almost completely seated. In park it idle at about 1100 RPM when I put it in drive it drops to 500 and then slowly continues down till it just dies. I have installed the electric choke with little change. I looked online and found several resources indicating Carter BBD's have idle issue. I found one site that indicated they tend to flood the engine at idle with leaky venturi's. I have another rebuild kit coming does it make sense or am I crazy?
Author:  DusterIdiot [ Tue Jul 16, 2013 7:02 pm ]
Post subject:  Did you?
How many turns out from seated are the idle mixture screws? (the two screws under the fuel bowl at the throttle plate.)

If it dies on the low side, you may be too lean and need to back those guys out another 1/2 turn...when you mess with the fast and curb idle screws they just index the throttle plate...if they are too far open without enough gas being fed from the idle circuit, the engine is going to lean out, starve and die...

This can be confirmed in real time if you had an O2 sensor plumbed in where you'd see it fall off on the lean side. I would also hook up a vacc. gauge so you can dial the idle mix for best reading in gear and try for a 650/750 rpm low idle(I'd jack the rear end up and put on jackstands and have a buddy stand on the brake while in drive while you tune...that way if he lets off or the throttle overcomes the brakes you don't get run over....)

-D.Idiot
Author:  jhdeval [ Tue Jul 16, 2013 7:44 pm ]
Post subject: 
I started with them at 2.5 turns out and I am at about 1.25 turns out right now. I pulled the plugs the other day and they looked good but I only have about 75-100 miles since the first test run. I know there is no way to say the mixture screws should be X number of turns but is 2.5 where I should start?
Author:  DusterIdiot [ Tue Jul 16, 2013 8:08 pm ]
Post subject:  Yep...
2 to 2 1/2 out is a good start. When I ran my super six setup on a much milder engine I think I had to vary the setting at about 1 1/4 turn out on colder months with a best of 3/4-1 turn out during the summer.

I would use the vacc. gauge to know when it starts to lean out and get low vacc. just before it goes too far and dies, always tune for best vacuum.

-D.Idiot
Author:  nzpete [ Wed Jul 17, 2013 12:51 am ]
Post subject: 
thanks for the heads up with regards to the venturi tubes. Another thing I have to check. I see that it is common with Jeeps, is it common with the Valiant carb as well or are the tubes different?
I've been having idle trouble with mine, but mine is intermittent, sometimes it idles smooth, sometimes not. i've been thinking it was maybe a needle and seat / float level problem but have not been able to sort it. The only thing with the venturi tubes theory for me though, is that it wouldn't be intermittent I would have thought???
Anyone with any suggesting, sorry if I'm hijacking the thread. :?:
Author:  jhdeval [ Wed Jul 17, 2013 7:47 am ]
Post subject: 
Okay so I think the issue maybe the choke. This morning I noticed that the clip that holds the choke rod to the choke lever had tension on it so I grabbed the rod and pulled up slightly. The clip popped up and off the rod. It appears the clip can not be in place and get fully "choked". I took the clip off and the choke moves freely.

I also noticed some index marks on the back can anyone explain how to use them?
Author:  Reed [ Wed Jul 17, 2013 8:49 am ]
Post subject: 
The index marks on the choke are to guide you with fine tuning it. The CarbsOnly kit is a great kit, but it has to be set up right. I installed one on my brother's 83 Dodge van and I had to bend the mounting tab slightly and adjust the choke.You may need to bend the mount very slightly until you have smooth movement of the choke rod and no undue tension on the clip.

To adjust the choke you have to loosen the screw on the ring around the perimeter of the choke coil housing. This should let you rotate the housing. You want to adjust the choke housing until the choke just barely closes fully when the motor is completely cold.
Author:  jhdeval [ Wed Jul 17, 2013 11:44 am ]
Post subject: 
Thank you Reed. I "Adjusted" the base a bit and it seems to be functioning better. I have not put the clip back but that because I dropped it under the car somewhere. lol
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