Re: Carter AVS tuning problem
[Re: MOPAULY]
#1454754
06/18/13 11:08 AM
06/18/13 11:08 AM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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I'd leave the top on as the floats are OK. Wait for someone who knows that system
live every 24 hour block of time like it's your last day on earth
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Re: Carter AVS tuning problem
[Re: MOPAULY]
#1454758
06/18/13 12:12 PM
06/18/13 12:12 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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That is surprising that it is way rich at idle since it was an emissions carb. If the main metering is lean you can convert to the Eddy 2 step rods/shorter pri jets. go a couple of tho richer than whats in there now for a start at least on the "cruise" step & fill the domed metering rod caps with JB weld then cover it with scotch tape then turn it over so the JB will settle flat/even on the tape & let it setup like that for several days
live every 24 hour block of time like it's your last day on earth
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Re: Carter AVS tuning problem
[Re: MOPAULY]
#1454759
06/18/13 12:32 PM
06/18/13 12:32 PM
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Joined: Feb 2005
Posts: 28,312 Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
I did read up on that a bit, I guess part of an emissions control they were trying to do. I wonder if it's worth messing with beyond this point or just replacing it with something newer. I plan to drive the car quite a bit once it's road ready and the rich idle is pretty obnoxious.
This reminds me of a recent tuneup I gave my car. 600 1405 edlebrock carb on a 340 with a 474 cam.
I got the vacuum gauge and timing light out. I didn't change my timing, 24 initial and 35 total plus vacuum advance.
What I did windup doing is open my idle mixture screws a little and that helped my idle. But also what I think it did was got rid of some of the smell from my exhaust. I have always thought rich idle caused the smell, but I'm now thinking it was a too lean of a idle causing some of the smell? At least in my case.
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Re: Carter AVS tuning problem
[Re: Challenger 1]
#1454761
06/18/13 12:41 PM
06/18/13 12:41 PM
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Joined: Feb 2003
Posts: 10,209 Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,209
Someplace you aren't
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Can you get the plugs out and tap it for regular AVS mixture screws? I've never had an AVS with the plugs. Mine always had screws and I could get the idle set right where I wanted it. I think the only ones I have had were 69-71 model carbs.
I want my fair share
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Re: Carter AVS tuning problem
[Re: Jim_Lusk]
#1454763
06/18/13 03:01 PM
06/18/13 03:01 PM
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Joined: Jan 2003
Posts: 7,843 Spring Mount, PA
MOPAULY
OP
master
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OP
master
Joined: Jan 2003
Posts: 7,843
Spring Mount, PA
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Quote:
If you have that screw all the way in (counter clockwise) that is the richest setting. They have left hand threads so that leaner and richer are the same rotation as a fuel screw.
The manual tells me the opposite? fully seated is lean? right now it's fully seated, rpms go up if you turn clockwise and back it out.
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Re: Carter AVS tuning problem
[Re: Jim_Lusk]
#1454764
06/18/13 04:04 PM
06/18/13 04:04 PM
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Joined: Jan 2003
Posts: 7,843 Spring Mount, PA
MOPAULY
OP
master
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OP
master
Joined: Jan 2003
Posts: 7,843
Spring Mount, PA
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Wait, are you saying that full in is all fuel and no air? I may be misunderstanding the purpose of this adjustment...if that is the case, this thread answers it and I've been adjusting it backwards: https://board.moparts.org/ubbthreads/showflat.php?Number=7637012&page=0to that point good thing I didn't have the impact on full hammer when I took the driver side wheels off as they are reverse thread, I didn't realize there were still doing that in '68.
Last edited by MOPAULY; 06/18/13 04:06 PM.
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Re: Carter AVS tuning problem
[Re: Jim_Lusk]
#1454771
06/18/13 09:17 PM
06/18/13 09:17 PM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
master
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master
Joined: Jan 2003
Posts: 9,436
Blair County,PA
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Quote:
I believe what you are describing is a backfire device, but I could be mistaken...
Actually it is a hot idle compensator and not on a 68 carb,also,to SCG,there are mixture screws behind the plugs.Here is one with the plugs removed and mixture screws installed.
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Re: Carter AVS tuning problem
[Re: 62maxwgn]
#1454772
06/19/13 01:19 PM
06/19/13 01:19 PM
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Joined: Jan 2003
Posts: 7,843 Spring Mount, PA
MOPAULY
OP
master
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OP
master
Joined: Jan 2003
Posts: 7,843
Spring Mount, PA
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Quote:
Quote:
I believe what you are describing is a backfire device, but I could be mistaken...
Actually it is a hot idle compensator and not on a 68 carb,also,to SCG,there are mixture screws behind the plugs.Here is one with the plugs removed and mixture screws installed.
any real benefit to this? It will eventually get replaced with a holley so I don't know if I'd bother with it. Plus it takes away from the resto factor should I get to that point.
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Re: Carter AVS tuning problem
[Re: MOPAULY]
#1454774
06/22/13 10:18 AM
06/22/13 10:18 AM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
top fuel
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top fuel
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
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If all the circuits are working well besides the curb idle, it seems like it would be worthwhile to do some extra cleaning in that circuit. Fine stuff settles in low spots and odd corners and sometimes plug things up even after a typical cleaning and rebuild. If it was my carb, I'd start with removing the air bleed screw and spraying in there, followed with some air if you have. While doing it, look to see if fluid is coming through the idle ports evenly. Because the air bleed feeds into the idle circuit, cleaning fluid should be coming out into the venturies. Next, I'd remove the plugs for the idle fuel restrictions. According the MTSC booklet '68 Service Features' Carburator Clinic there are limiter screws underneath. Count the 1/8 turns in to seated, write down, and then remove. Spray in there and again make sure fluid is coming out each idle port. Reinstall limiters. Again if it was me, I'd try it without resealing the limter screws. That way IF the air adjustment screw does not provide the desired range, the limiter screws can be played with. Its actually pretty cool that you can adjust the air bleed as well as the fuel restrictions with the turn of a screw driver. (easy for me to say, since I don't know how easy it is to get a screwdriver into those restrictors whe the carb is on the engine!) But heck if I had that carb, I'd be playing with it. If you ever want to show as a restoration, you can put plugs back over the limiter screws. Besides the shop manuals and the Service Features pamphlet, there is a an entire '68 MTSC pamplet 1968 Carburator Service Highlights at Imperial club org to check out.
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Re: Carter AVS tuning problem
[Re: pjc360]
#1454777
06/22/13 04:01 PM
06/22/13 04:01 PM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
master
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master
Joined: Jan 2003
Posts: 9,436
Blair County,PA
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Quote:
I'll bet there is a vaccum leak at the throttle shaft's. Spray carb cleaner around the throttle shafts with it idling fully warmed up and i bet the idle smooths out.
There are "very" few that don't leak some at the throttle shaft,idle mixture adjustment will take care of that.
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