Author Topic: Plug reader needed.  (Read 2301 times)

Offline 71bigblock

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Plug reader needed.
« on: September 09, 2007 - 08:36:07 PM »
I would guess I'm running rich?  The plugs are from cylinders 5 and 2.  Its a '69 Carter AVS.  It has 89 jets in the primaries, and 82 jets in the seconds.  Can I fip those around?  Please help a carb dummy out, and if I can switch them, how?  Also, at I would guess around 3000-3500 RPM it starts missing, is it not getting enough gas then? 




Offline matt63

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Re: Plug reader needed.
« Reply #1 on: September 09, 2007 - 09:28:46 PM »
You can check out a number of web sites with decent plug reading advice and pics.  I would say your plugs look okay based on what I know.  The base ring is fouled which indicates a rich idle as your garage floor indicates.  I know nothing about AVS carbs so I don't know how to adjust the idle mixture.  I would guess there are mixture screws at least.
Missing at running speeds is typically ignition and/or ignition timing related.
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Offline 71bigblock

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Re: Plug reader needed.
« Reply #2 on: September 09, 2007 - 09:46:58 PM »
You can check out a number of web sites with decent plug reading advice and pics.  I would say your plugs look okay based on what I know.  The base ring is fouled which indicates a rich idle as your garage floor indicates.  I know nothing about AVS carbs so I don't know how to adjust the idle mixture.  I would guess there are mixture screws at least.
Missing at running speeds is typically ignition and/or ignition timing related.


I have 2.76 gears, and when I kick it down at about 50 mph or so, I get up to about 60 and it starts missing.  I have pertronix ignition, the one that goesn in the distributor.  I did adjust the idle screws once, and turned them down quite a bit. 

Offline 70challengerrt

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Re: Plug reader needed.
« Reply #3 on: September 09, 2007 - 09:57:51 PM »
The idles screw I usually turn in until the rpms starts to drop then out 1 turn. I go back and forth between the 2 screws. I tend to go a little rich, sure beats too lean. The plugs look fine. Is your fuel filter getting pluged and only letting a little fuel through. I had it happen to me and it stumped me for weeks, I would go down the road but if I need to much fuel or accelerated to fast it would stumble.

Offline Chryco Psycho

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Re: Plug reader needed.
« Reply #4 on: September 10, 2007 - 02:28:18 AM »
looking at your pix it doesn`t look rich to me , it should be tan on the center electrode , you may be lean at 3000

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Offline 71bigblock

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Re: Plug reader needed.
« Reply #5 on: September 10, 2007 - 09:39:22 PM »
looking at your pix it doesn`t look rich to me , it should be tan on the center electrode , you may be lean at 3000

OK CP, I put my specs into an RPM calculator, and I got 3300 RPM in 2nd gear @60 MPH, and its right then it misses real bad, and wont rev higher.  What do I do?  Drill out the secondary jets?  And how would I go about it? 

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Re: Plug reader needed.
« Reply #6 on: September 10, 2007 - 09:42:49 PM »
Mopar Muscle December 2006 shas a tech article on plug reading and shows up close pic... its also the issue goody got his cuda in  :burnout:

Offline moper

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Re: Plug reader needed.
« Reply #7 on: September 11, 2007 - 12:29:23 PM »
Plugs look decent to me. Maybe a little lean, but not terribly.

Offline Chryco Psycho

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Re: Plug reader needed.
« Reply #8 on: September 12, 2007 - 01:57:51 AM »
HAve you confirmed the secondaries are opening ?, sometimes they will hang up on a gasket or the intake is too small
 have you checked the flaot levels , generally 7/16" at the tip of the float , do you have a fuel pressure guage ?
I doubt it has to do with jetting if it simply stops at 3300 rpm

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Offline 71bigblock

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Re: Plug reader needed.
« Reply #9 on: September 12, 2007 - 10:22:50 AM »
Yes, the secondaries do open, I made sure of that.  I have checked the float level twice, I could check it again, its not that hard, just kind of a pain.  I dont have a pressure guage, but I suspected that my fuel pump was weak to begin.  Reason being, I started my car while my dad held the fuel line (removed from carb) and it took about 5 seconds to pump.  But it did pump like crazy when it did.  It doesnt stop at about 3300, just is missing like crazy, then I back off.  Thanks CP.  What is the normal jet size for the secondaries for a Carter AVS 625?

Offline MyMopar

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Re: Plug reader needed.
« Reply #10 on: September 12, 2007 - 11:19:22 AM »
Fuel pressure gauge is a must have when dealing with these problems.  I got an electrical one and put it in my glove box, helped solve my problem of not revving over 4000, turns out pinched fuel line.  Make sure you don't have any sharp turns or bends in the rubber hose and also make sure it is not squishy.
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Offline Chryco Psycho

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Re: Plug reader needed.
« Reply #11 on: September 12, 2007 - 11:59:09 AM »
not sure where to look for he stock jet size for that carb

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Offline MOPAR FANATIC

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Re: Plug reader needed.
« Reply #12 on: September 12, 2007 - 12:51:11 PM »
 :dunno: if this will help steve,but my 383 upgrade to electronic ignition took care of the same problem i had on my charger years ago.i had the same miss and that took care of it.just a thought.  :thinkerg:
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Offline MOPAR FANATIC

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Re: Plug reader needed.
« Reply #13 on: September 12, 2007 - 12:53:57 PM »
 :dunno: was it running the same when you had the 2 bbl on it???????
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Offline 71bigblock

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Re: Plug reader needed.
« Reply #14 on: September 12, 2007 - 01:02:27 PM »
:dunno: was it running the same when you had the 2 bbl on it???????

It actually runs better now with the 4 bbl, it doesnt hesitate or miss at idle.  The 2 bbl never missed above idle though.  I do have the pertronix kit in the distributor, but only the stock coil still.