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Plug pics. Tuning help needed, metering rods and jetting question

Evan, you should not have to drill any holes in your butterflies. We are explaining what some people do to try n doctor things up to get them to work.
Id take carb off to really clean out the float bowls and to make sure your jets are free n clear of debris. once carb is off just rotate to see the idle screw slots on inside of venturis are covered by butterfly when they are closed. If you see the idle slots when butterflies are closed, you need to monkey with timing. As Bob mentioned make sure the carb base gasket does not cover up any idle passages on base of carb, and make sure intake manifold if it has any vac ports on carb mount arent covered up. Its so you dont chase your tail trying to tune the motor.
once you do get it running, put a vaccum gauge on the one of the vac ports on carb. Again google or you tube how to use vacuum gauge to assist in tuning your motor. You'll find all kinds of neat info you can use by utilizing a vac gauge, if your timing is off, weak valve springs, cam timing, leaky valve seats etc.
 
Well I just checked it out from the top of the carb and could clearly see what your talking about... and was able to determine I probabaly have my idle speed adjustment turned too far in, causing the butterflies to be slightly open, and sort of exposing those slots...

One thing I have never understood is what the idle speed screw is supposed to be set to?

The idle mixture screws will kill the engine if turned in all the way. When turning the screws out, the idle speed stops getting faster at about 1.5 turns.

I got the new distributor in the mail today and the vaccum advance clearly works. The car runs better. With a timing light I have my idle set to about 700 in neutral ( auto trans)... but the RPM does drop a lot to the point of wanting to die once I put it in gear. Initial advance is set to 16 degrees. Should I go higher, and how much might it want?

I wondering if that drilling mod you mention might help? I've been dealing with a bad, slow idle for a long time now.

Currently, even with the new distributor, and straightened out metering rod, and floats now set properly.... still, in order to get it running better when idling in gear, I would need to set the idle speed to about 1000 in NUETRAL. Then it would drop to about 700 once I put it in DRIVE. What does that tell you?

It's definitely running better with the new distributor and after cleaning all the plug wire connections and such. But still doesn't like to idle. And the idle RPMS drop excessively when I put it into gear.

I don't likely have a vaccum leak. New distributor. Brake booster rebuild by Dewey. The flanges are all leak free. New vaccum lines... etc. I was careful when I installed it.

The carb was cleaned of all debris
 
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Evan Frucht said:
Well I just checked it out from the top of the carb and could clearly see what your talking about... and was able to determine I probabaly have my idle speed adjustment turned too far in, causing the butterflies to be slightly open, and sort of exposing those slots...

One thing I have never understood is what the idle speed screw is supposed to be set to?

The idle mixture screws will kill the engine if turned in all the way. When turning the screws out, the idle speed stops getting faster at about 1.5 turns.

I got the new distributor in the mail today and the vaccum advance clearly works. The car runs better. With a timing light I have my idle set to about 700 in neutral ( auto trans)... but the RPM does drop a lot to the point of wanting to die once I put it in gear.

I wondering if that drilling mod you mention might help?
Don't drill the butterflys.. Check Chiltons idle in neutral is like 1100 , once you put in gear of course it will drop rpm level.
If you have rpm in neutral set to 700rpm, with an unknown cam... eg 3/4 race grind you'll need to up the idle n timing a tad.
gently seat the idle screws, back out 1.5 turns to start.
the idle screw I would back it out to where it stops at the rest and turn screw in 3 or 4 turns, just enough to see butterfly open a tad. Its a dance between idle screws and timing, go back and forth to find happy medium, especially when motor is cold and choke is set, and hope you don't get starter kickback or run on when you turn motor off


I've been chasing this problem for a long time
Click to expand...
 
Thanks.

Ok I'll turn up the the idle speed screw tmrw and stick a vaccum gauge on some ports.

The problem is that the the 2 idle mixtures screws are already turned out a little bit over 1.5 turns. I am confident I set those right, and have done that many times before.

Timing is currently at 16 degrees initial. Seems on the high side to me but I also have no idea what the PO did to the cam. Should I try it at around 18, 20, 22? What sounds like too much for this engine? I turned the distributor higher just by hand while the engine was running but it didnt seem to change the idle speed much after 16? ( I was watching the timing light while doing this)

And then.. the idle speed screw where it is at currently has already cracked open the butterfly about 1 or 2mm.

This is at about 700 or so in nuetral.

...So if I crack it open more to get the 1000ish in neutral the the butterfly will be open even farther. I think that also exposes those slots more (is that correct) ... or do the slightly open butterflies then counteract the extra fuel that gets in from those slots and even out the mixture?

I want to make sure I'm not running rich like before
 
Evan Frucht said:
Thanks.

Ok I'll turn up the the idle speed screw tmrw and stick a vaccum gauge on some ports.

The problem is that the the 2 idle mixtures screws are already turned out a little bit over 1.5 turns. I am confident I set those right, and have done that many times before.

Timing is currently at 16 degrees initial. Seems on the high side to me but I also have no idea what the PO did to the cam. Should I try it at around 18, 20, 22? What sounds like too much for this engine? I turned the distributor higher just by hand while the engine was running but it didnt seem to change the idle speed much after 16? ( I was watching the timing light while doing this)

And then.. the idle speed screw where it is at currently has already cracked open the butterfly about 1 or 2mm.

This is at about 700 or so in nuetral.

...So if I crack it open more to get the 1000ish in neutral the the butterfly will be open even farther. I think that also exposes those slots more (is that correct) ... or do the slightly open butterflies then counteract the extra fuel that gets in from those slots and even out the mixture?

I want to make sure I'm not running rich like before
Click to expand...

If your main idle screw is barely turned to open the butterflies, you should be ok to open it up some more. if you have another carb kicking around, turn base idle screw while looking up from bottom to see a ball park how much you can turn screw before idle transfer slots are exposed. You can open main idle set screw some more, if your base rpm is so low, you arent getting enough air in the motor, and it can cause a rich condition. If you have a trustworthy assistant have them start car ...be careful here, have them put car in drive while they have foot on the brake, and with it in gear, brake on, set rpm up to 900rpm see what that does for you
if you have 16 degrees advance and vacuum line is disconnected from carb and idle does not pick up any more, I'd say you are maxed out with timing.
Now with a vaccum gauge, goal would be to see a nice steady vac reading at idle. now you might get some fluctuations due to cam profile. But seriously google tuning with vac gauge, there is a ton of stuff out there and once you see it , things will become easier to grasp.
 
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Ski 61701 said:
If your main idle screw is barely turned to open the butterflies, you should be ok to open it up some more. if you have another carb kicking around, turn base idle screw while looking up from bottom to see a ball park how much you can turn screw before idle transfer slots are exposed. You can open main idle set screw some more, if your base rpm is so low, you arent getting enough air in the motor, and it can cause a rich condition. If you have a trustworthy assistant have them start car ...be careful here, have them put car in drive while they have foot on the brake, and with it in gear, brake on, set rpm up to 900rpm see what that does for you
if you have 16 degrees advance and vacuum line is disconnected from carb and idle does not pick up any more, I'd say you are maxed out with timing.
Now with a vaccum gauge, goal would be to see a nice steady vac reading at idle. now you might get some fluctuations due to cam profile. But seriously google tuning with vac gauge, there is a ton of stuff out there and once you see it , things will become easier to grasp.
Click to expand...

Well I made the fatal error of not setting the initial timing with my new functioning vaccum can disconnected. I knew I was supposed to do that but forgot. Thanks for clarifying everything. I will continue working on it tmrw and report back
 
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Evan Frucht said:
Well I made the fatal error of not setting the initial timing with my new functioning vaccum can disconnected. Thanks for clarifying. I will continue working on it tmrw and report back
Click to expand...

Evan, its how we learn.. takes more of man to say that he made an oops. Respect from this guy!.
Yeah, redo timing tomorrow and see the difference. once you get base timing set. Apply vaccum to advance pod and you'll hear the rpms increase.
You'll get this ironed out.
 
Evan, if you go to studebaker-info.org it explains the basics and proper order of doing a carb / timing its a Good read. When you search that website look for tune with a vacuum gauge. Good information for you.
 
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Ski 61701 said:
Evan, if you go to studebaker-info.org it explains the basics and proper order of doing a carb / timing its a Good read. When you search that website look for tune with a vacuum gauge. Good information for you.
Click to expand...
Thanks
 
Ok so here is a little update.

I have an older Snap-On timing light so hopefully its pretty accurate. My vaccum gauge is from Harbor Freight but seems to work fine.

I re-adjusted my initial timing to what looks about 17 or 18 based on the flywheel markings. The engine seemed to like it right about there. It didn't speed up my idle past that point and would actually idle worse with more. A little less seemed like it would have been ok tho? But when I took it for a drive I didn't hear any detonation, it seems snappier and actually sounds a little better, a little meaner, a little leaner maybe ?

I backed out out the idle screws about 3 full turns. The idle stopped getting faster at about 2.5 or so turns but I want to avoid fouling my plugs like before. Before they where turned in closer to the 1.25 recommended.

Idle speed screw backed out a good few turns until I reached ~900rpm in NUETRAL. I could see the timing light through my dash and when I put it into DRIVE with foot on brake it went down to ~600rpm. It has a slight slope to it but sounds good, better than before.

I tested the VACCUM and have no vaccum at idle. The gauge shows 0. Then at ~1100rpm its 15psi. At ~1200 its 20psi. By 1500 rpm it is at 30. Near 2000 rpm it goes to 50... and that's all I went too.

Does this all sound like it should be good. Nothing I did threw up any red flags or anything ?

On a side note I could hear my old starter going bad and I replaced it with a remanufactured unit from Napa for a '96 Dodge Dakota. That thing is bad ***! Starts instantly and is much easier to install since its smaller.
 
If your maximum RPM was at 2.5 turns then you should be slightly in from there (less fuel) try 1/4 turn in from there. So about 2 -1/4 turns.
It's somewhat common to have one side be more responsive than the other.
If you do set the other screw based on the one that is more sensitive, count the turns and duplicate the setting.
Vacuum is measured in inches of mercury and I dont' think you have 50 inches?
Sometimes gauges have multiple units on them maybe your reading the wrong scale.
 
Don Frelier said:
If your maximum RPM was at 2.5 turns then you should be slightly in from there (less fuel) try 1/4 turn in from there. So about 2 -1/4 turns.
It's somewhat common to have one side be more responsive than the other.
If you do set the other screw based on the one that is more sensitive, count the turns and duplicate the setting.
Vacuum is measured in inches of mercury and I dont' think you have 50 inches?
Sometimes gauges have multiple units on them maybe your reading the wrong scale.
Click to expand...
Ok thanks, I think someone on this thread mentioned turning the idle mixture screws out more would make the idle leaner. I guess not tho. I'll address that.
Yes I'm not sure the units of measurements I was referring to but that's what the gauge was showing. Lemme look at it and report back.
Overall the car is running better and has yet to miss a beat
 
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