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Unread 08-07-2013, 10:35 AM   #1
jbrosnan
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Tuning my 85 CJ7

First of all I would like to thank everyone for the information on threads I have posted so far, I have learned a wealth of knowledge and got my CJ running to this point.

So far I have cleaned the tubes in the venturi and got the thing to run pretty fair. I held off doing a tune up due to problem getting the title. I now have the title and the first thing I have done is the team rush modification, I believe it has boosted the power noticebly. I would like to do the Nutter bypass next, but my wiring and vacuum lines are a mess, I am going to have to trace the wiring to see how it is before I start cutting and splicing, the vaccum lines are sure enough a mess I dont think any of them are anything like what I have seen on the thread to do the Nutter.

My big question of the day is what adjustments can I do to the carburetor, when idleing the jeep smokes so I assume that this is too much fuel and not enough air correct? Remember I am a shade tree mechanic, so when the term rich and lean are used does that mean fuel rich and fuel lean or does it mean air rich and air lean? Again any suggestions on tunning the Carter BBD?

Also when I did the team rush I left the cannister coil, it is a original AMC part. Should I go ahead and replace it?

Again thanks for all the help up to now and in the future.

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Unread 08-07-2013, 10:39 AM   #2
LumpyGrits
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First you need to confirm that the smoke is NOT from oil.
Do a compression and leak-down test.
How many miles on the engine?

LG
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Unread 08-07-2013, 01:14 PM   #3
jbrosnan
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I am pretty sure that the smoke is fuel and not oil, the engine uses very little oil and most of it leaks out the rear main on my floor, it does not seem to use as much once it is a quart low. I do need to perform a compression test though. The engine was fairly new when I got the jeep supposedly about 200 to 300 miles. As far as in my other post the plugs were black but were dry, the dizzy cap, plugs, and wires were replaced yesterday when I peformed the team rush upgrade. I didnt do a tune up till now because that was all new when motor was installed.
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Unread 08-07-2013, 01:30 PM   #4
LumpyGrits
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On the very off chance you have a bad plug.
Switch it with another from the ones you have.
What plugs are you running?
LG
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Unread 08-07-2013, 08:03 PM   #5
86cj74.2L
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Is your choke plate open all the way when engine is warm?

How long was the CJ sitting before you got it on the street?

It could be as simple as your float height is too high.

As for tuning, its a carb setup for the 258. If its put together correctly and adjusted as per the instructions it works.

Two things will make it run poorly.......

One is vacuum leaks will cause it to run rich (too much fuel) between idle and 3/4 throttle, and the other is worn throttle shaft bushings. Worn bushings usually only cause a idle that seems to be high or low depending of how far the plates shut and a off idle hesitation.

Black smoke is too much fuel. Way too much fuel. Your idle mixture screws should be around 2 1/2 turns out from lightly seated. Anything beyond 3 to 3 1/2 is a indication of vacuum leaks.
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Unread 08-08-2013, 12:06 AM   #6
LumpyGrits
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Vac leaks cause a lean condition from excess air in the fuel mix.
LG
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Unread 08-08-2013, 12:41 AM   #7
86cj74.2L
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Quote:
Originally Posted by LumpyGrits
Vac leaks cause a lean condition from excess air in the fuel mix.
LG
On a carter a vacuum leak will cause the step up piston to ride higher in its barrel which raises the needles for the same throttle position. Which richens the mixture. The needles will move about 1/4 inch against the spring under the barrel. Vacuum keeps it pulled down against the spring placing the needles in their leanest position.
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Unread 08-08-2013, 08:40 AM   #8
LumpyGrits
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Once the needle stops and the v'leak is enough. It will cause lean condition as in any other fuel delivery system.
Respectfully,
LG
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Unread 08-08-2013, 12:53 PM   #9
86cj74.2L
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You are correct but its the minor leaks that drop total vacuum 3-5 numbers that you can't hear.

Like the intake manifold bolts being loose.
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Unread 08-08-2013, 01:39 PM   #10
LumpyGrits
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Those Carter BBD's were designed by the devil itself.
LG
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Unread 08-08-2013, 01:57 PM   #11
86cj74.2L
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They are the same basic design as a Rochester 4bbl and the carter AFB (and its clones)

Knowone here bashes them and the Rochester is basically two of them with more linkage rods.
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Unread 08-08-2013, 02:12 PM   #12
LumpyGrits
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Carter AFB's were easy, and didn't the 'puter or mini-passages that would clog with a micron sized piece of crud.
Carter AFB was the first carb I ever rebuilt in the 60's
LG
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Unread 08-08-2013, 09:24 PM   #13
jbrosnan
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LumpyGrits I put autolite copper plugs in when i performed the team rush upgrade the other day, I gapped then at .045", not sure of the number but I looked up the plugs for that model and that is what I got. My biggest concern now is getting all the dan vacuum lines somewhat the way they need to be so I can then evaluate the carb. I have looked at some diagrams folks have posted and my vacuum lines are not like any, my ported vacuum port on the passenger side of the carburetor had no hose or cap on it, there is some kind of fitting with several vacuum lines on it bolted to the top of the valve cover not sure what that is. I am a newbie and just want to get what I need ran correctly and get rid of what I dont need. THe jeep now runs pretty good but idles a little ruff and as I said it smokes when ideling. I appreciate the help and could use all of the help to come.
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Unread 08-08-2013, 09:54 PM   #14
LumpyGrits
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You REALLY need a copy of the REAL Factory Service Manual(MR-252). It has the vac line routing.
LG
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Unread 08-08-2013, 10:23 PM   #15
86cj74.2L
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Readjust your fuel mixture screws for lean best idle and see if that helps your idle.

Those three things bolted to your VC are for the air injection and the SOL-VAC. Not too important.
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