• Welcome to ClassicBroncos! - You are currently viewing the forums as a GUEST. To take advantage of all the site features, please take a moment to register. It's fast, simple and absolutely free. So please join our community today!
    If you have problems registering or can't log into your account, please contact Admin.

Carb running rich at part throttle.

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
So been struggling with carb issues and a coil breaking down when hot. Replaced the coil and sent the carb out to Guarantee carb in FLA. My question is now as I throttle it up it wants to black smoke. When I drive it and throttle it up it smells like it's rich. I have fooled with the idle air screws , but to my knowledge these to nothing once throttle is given . They where set about 5 and half turns out when I got it back . I turned them in to around 4 turns out. If i turn them in to say 2 1/2 turns it runs very poorly. At 4 it runs very smooth and on the vac guage it holds almost 20. Do i need to step it down jet wise? I'm not a real good carb turner , but a decent mechanic and willing to learn thanks Lance .
 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
Well it has ran good, just the rich issue when throttling it up. I always expect some type of tuning on a carb. So not really there fault or not yet anyway.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,179
Maybe there’s simply too much squirter from the accelerator pump. Can you tell where it’s set now?
And as said, what carburetor?
 

bax

Contributor
Old Member
Joined
Aug 22, 2005
Messages
13,963
Did you read their business reviews? Lots of haters there. Again, what kind of carb? I am sure we can help you out.
 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
It is a autolite 2bl. 1.08 vent. The pump is set in the 2nd hole down on the linkage. I tried moving it up and down with minimal results . I did read the reviews or some. Some online said they did a good job. Some didn't, but hard to say about online reviews , some people just can't be pleased.
 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
No didn't give anything as far as jetting goes. Choke was a heat stove style , but the changed it to electric, but right now I have it completely off, so choke stays straight up and down all the time.
 

TX-ZACH

Contributor
Newbie
Joined
Sep 27, 2021
Messages
131
Where the timing at? Someone once told me here go back to the timing and then adj the carb.
 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
Haven't looked at the timing because it didn't smoke prior to the carb rebuild. I took it off because it would run like riding a horse at 50 miles an hour kind of like a surge at highway speeds. I pulled the carb apart and the two brass tubes under the booster where cracked on both sides. Sent it in for a rebuild and change that out. Now at part throttle or so it wants to smoke black. Plugs are burning clean and not gas fouled. No kick back on the starter or hard starting.
 

i3adme

Contributor
n00b
Joined
Nov 20, 2020
Messages
26
Are you running a fuel pressure regulator? Mine bucked like you described shifting into 3rd. I’ve got a 4011 Holley. Didn’t think I needed one with my manual pump, but when I attached a pressure gauge it would go as high as 9psi at higher rpm’s. Attached a pressure regulator at 4psi and it was like night and day.
 

blubuckaroo

Grease Monkey
Joined
Jun 11, 2007
Messages
11,735
Loc.
Ridgefield WA

Lance, seeing that you've just had this issue since having the carb refurbished, I'd start by checking out their work. It's easy to open it up for an inspection. I'd start by checking the fuel level. this needs to be done on the car, with the carb top off, and the car running. Your carb may have been rebuilt, but each application for that same carb will have its own specific fuel level spec.​

Then, I'd pull the carb off, flip it over, and replace the power valve, since there's no easy way to test it for leaking and causing a rich condition.​

 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
All right guys , feel free to chime in. My timing light burnt up so i dont have one right now, but will buy another one soon. Any way like i said timing seemed good , but i bumped it up. Wrong thing to do ran like shit smoked worse and spark knocked. So back to where it was at and ran good, just black smoked when i gave it throttle. Rechecked the idle air bleeds, there 4 turns out vac gauge holds 20 inch's steady there. So i unhooked the pump shot from the accelerator pump rod. With it undone when i give it fuel it doesnt smoke. I know it will stall unhooked , so i put it in the lowest hole in the throttle linkage. Runs good there with out any real issues. So im going to drive it for a few days to see what and how it does. I know in some aspects im kind of band aiding something but it works. Any ideas on what to do from here or just leave it alone? Thanks Lance
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,179
Which port are you using for vacuum advance? Does it give full vacuum at idle?
If so, that might explain the bog, as when you open the throttle the advance actually retards some until it catches up.

It can work that way, but it takes some doing to tune out the downside if you want to run full vacuum.
And do you have a dual port advance can, or single?

Paul
 

Rustytruck

Bronco Guru
Joined
Feb 24, 2002
Messages
10,714
pop the top and check the float level. Bronco jets on the stock carb run from 47 to 52 normally the are stamped on top or side of the jet. just are not in play during idle and mid transition. set your idle at highest steady vacuum reading. at 700 rpm idle. High float levels and cause the issue in the transition.
 
OP
OP
4

428kidd

New Member
Joined
Mar 7, 2022
Messages
29
Ok I will try that. When I pop the top off how will I know if the float level is good? Thanks Lance
 

EPB72

Contributor
Sr. Member
Joined
Jul 13, 2019
Messages
628
Loc.
Pleasant Hill, CA
Ok I will try that. When I pop the top off how will I know if the float level is good? Thanks Lance
If the float pivot pin retainer clip is properly installed and it should be,,,then you can acctually run the engine with the carb top removed..to check wet float level and compare with specs..
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
43,179
Does anyone know the specs specifically for this one? And do they still include one of those heavy fiber paper gauge tool thingies in the rebuild kits?
I’ve got a lot of those laying around, but thinking about it I should’ve been making big bold pen marks on each one so that at a glance I can tell what carburetor they were for. Ugh, more work…
 
Top