Idle mixture setting double check

[evesdropper]

My carb is working fine now after rebuild. I need a spot check to make sure I did this right...

To adjust the idle mixture, I:

1. removed a square head plug from the firewall side of the manifold and attached a fitting and my vacuum gauge
2. hooked up the distributor vacuum advance, choke pull-off and CTO ports 1 and 5 to ported vacuum
3. hooked up the EGR to CTO port 4
4. started the jeep and raised the idle speed to 800'ish (manual Transmission )
5. turned the idle mixture screw clockwise until it stumbled, then back counter-clockwise until i got the highest reading
6. adjusted the distrubutor until it ran the best and reset the idle to 800

My concerns are:

1. Maximum vacuum I was able to get was 18-19. This seems on the low end. Is this ok?
2. oil pressure gauged only ever read 5-10psi. it would go up to 20 when rev'ing the engine. This seems low also. It is the stock gauge and sender. Should I be worried?
3. Electric choke is not connected (i wedged it open after the engine was warm). There is not a oil pressure sensor switch to run a wire to like I see on the AMC 258 i6 / 4.2l 's. I hooked it up direct to the battery to test and after 5 min, nothing had happened. Is it worth replacing the electric choke or would you recommend just swapping it with a manual control? I have the manual parts from a junk carb.

I can't see the timing mark on the balancer for all the rust. If it is running ok, my thought was this was the least of my worries. I will wire-brush off the rust and spray paint the balancer. Once I find TDC, I have a MSD timing tape I can stick on it.

Anything I missed or did wrong so far? Thanks for the help

Poor phone video. the big fuzzy number the needle is close to is 20.

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[Lumpy Grits]

What is the altitude(ASL)where you live? That affects vac. reading.
18-19in at hot idle with stock type cam, is good with a steady needle
The OEM oil gauge is a POS-Never trust them.
Here's what you want-
Oil Pressure Gauge. Black Dial, Mechanical Oil Pressure Gauge.
LG

 

[evesdropper]

What is the altitude(ASL)where you live? That affects vac. reading.
18-19in at hot idle with stock type cam, is good with a steady needle
The OEM oil gauge is a POS-Never trust them.
Here's what you want-
Oil Pressure Gauge. Black Dial, Mechanical Oil Pressure Gauge.
LG

I am at about 1100'. The carb however is the 7703 high altitude model. The CJ8 is from Colorado I believe.

I will pick up a mechanical gauge.

 

[Lumpy Grits]

If it's tuned for hi-alt.
Then you may very well run lean-'Read' you plugs and you may well have to re-jet.
Lean fuel mix will kill an engine PDQ-
LG

 

[evesdropper]

I double-checked and it is the 7702 yfa carb for high-altitude. If I want it to run the best it can, I guess I need to swap the metering rod to part# 75W-8522 (I think I have one) and the jet to #120W-2410 (0.110 in). I will get on that. Thanks.

 

[Lumpy Grits]

Listen to your spark plugs('read' the tip color).
I use Autolite 985.
LG

 

[evesdropper]

Listen to your spark plugs('read' the tip color).
I use Autolite 985.
LG

I will check them out tonight. Thanks.

 

[evesdropper]

OK. The plugs I pulled out were sooty, black and nasty. They had been in there for a long time when the engine ran with bad gas and a clogged carb so I replaced them with the autolite 985 you suggested.

I cant drive the jeep with no brakes so after idling at 800'ish RPM for 15 minutes, these plugs look better. The insulator has a little light brown color is all. No black oily or soot deposits.

I wire-brushed the balancer and found the tdc notch. I spray-painted the balancer black and installed the correct size msd timing tape. Now I can give more accurate diagnostic info.

At 800rpm, the jeep runs best at a whopping 25* timing . That is with the vacuum advance disconnected and source capped. It pulls 19-20 in hg on the vacuum gauge at that timing and with the idle mixture adjusted. This is the setting the plugs were checked with.

I was able to get it to run at 15* (vac advance disconnected) but it runs like garbage. No amount of idle mixture tweaking could get vacuum above 16 in hg and it misses something terrible. any lower than 15* and it wont start or dies if I turn it down to that.

I tried to map the advance curve when it was at 15* but the motor acts like it lost all power at about 1600 rpm.

I remain resolute in my goal of fixing this thing. I will soldier on with whatever advice you can give. Since I am going to use an HEI distributor on this anyway, maybe I should quit dinking around with the stock ignition system and just swap it and start from there?

 

[Lumpy Grits]

Sooty is over rich fuel mix. Is the float set correctly??
How does it run at 1200-1300rpm?
You have multiple issues going on here.
Have you done a compression ck? I think you should.
How old is the dizzy cap, rotor and wires?
When you replace the dizzy cap-Only use one with brass contacts. Best to go to NAPA here and get their best.
LG

 

[Jimbos76cj]

I wish i had more insight on the I4 for you. To me it sounds like your adjudting the carb correctly by the vacuum. As far as the timing goes I just did the same ordeal with my AMC 258 i6 / 4.2l , Timing set at 10* it idled smooth and ran well. as I bumped up the timing the vacuum would increase and seemed to be more agressive. Took it for a drive and it was awesome. I shut it down and could not get it to restart. after that I knocked it back down to 10 and it starts and runs fine.

 

[evesdropper]

Sooty is over rich fuel mix. Is the float set correctly??
How does it run at 1200-1300rpm?
You have multiple issues going on here.
Have you done a compression ck? I think you should.
How old is the dizzy cap, rotor and wires?
When you replace the dizzy cap-Only use one with brass contacts. Best to go to NAPA here and get their best.
LG

I was probably not clear. the sooty plugs were from before when it had bad gas and a messed up carb. The light brown on the insulators is on the new plugs. No soot on them after running for 15 minutes.

No idea on the age of the cap rotor and wires.

I think I have a compression tester someplace. I will try that and post those results if I find it.

No argument on the multiple issues thing. This is a pile of projects all rolled into one package. I need to get the motor running right if possible before I spend any more dough on the rest of the chassis.

 

[evesdropper]

I wish i had more insight on the I4 for you. To me it sounds like your adjudting the carb correctly by the vacuum. As far as the timing goes I just did the same ordeal with my AMC 258 i6 / 4.2l , Timing set at 10* it idled smooth and ran well. as I bumped up the timing the vacuum would increase and seemed to be more agressive. Took it for a drive and it was awesome. I shut it down and could not get it to restart. after that I knocked it back down to 10 and it starts and runs fine.

I have the opposite problem. If I adjust the timing to 15, it runs like garbage and won't start. If I adjust it to 25, it idles and starts great with 19 in hg. At that timing it has problems at higher than idle rpms though.

Compression test is up next as suggested. I don't have a leak-down tester but HarborFreight is not far away.

This is all very frustrating but I am learning stuff.

 

[Torxhead]

If you are questioning the ignition timing, you could verify that the vibration dampner location has not slipped and put the #1 pistion at tdc, making sure that it is reading at zero degrees. I would think the fuel mixture is on the rich side as Lumpy suggested.