I’ll try to give as much info as possible, my freshly rebuilt 352 FE with a 4bbl Autolite (also rebuilt but I’ve not seen it run on an engine before) is running rich at idle. It is not on the choke It sounds like it’s running rich It looks like it’s running rich A squirt of fuel in the carb makes it die Pressing the accelerator pump without the throttle makes it die It runs best with the idle mixture screws out about 1/2 turn Turning the idle mixture screws in any more to lean it off and it dies This all applies to both sides of the carb What has got me scratching my head is that if there was a problem other than the idle circuit then screwing the idle screws in wouldn’t kill it. If the idle circuit was too rich then leaning it off wouldn’t kill it. Timing is at 10 BTDC What am I missing??
Very mild cam, bottom of the Edelbrock catalogue, certainly not hot enough to cause poor burn at idle. Offenhauser 360 intake PCV system Stock pistons, new rings Stock ignition, mech and vac advance work Stock crank and rods, new bearings Stock heads, new valves and guides Stock fuel pump Not sure I trust my vac gauge as I noticed it’s not returning to zero, it was reading about 16” Carb is jetted for a 300hp 352 T bird
I wonder if the power valve or power valve gasket is bad. I agree though, you'd think turning the idle mixture screws in wouldn't kill it.
The reason why I don’t think it’s power valve is that i don’t think it runs through the idle circuit so if it was blown, screwing the idle mixture screws in shouldn’t cause the engine to die.
There’s a lot of talk about 4100 over on the Yblock site, they (and the new, similar Summit version) have been pretty popular in the 1.08 and 1.12 versions. Everyone seems to be more like 1 1/2 to 2 1/2 turns out. If you’re still rich at 1/2 turn there’s fuel coming from someplace. Or an air bleed blocked?
Fuel coming from somewhere other than the idle circuit would be my guess except for the fact that if you lean it off on the idle mixture screws it dies. Everything was stripped and blown through with air and carb cleaner when I rebuilt it.
Does that carb have any idle air bleeds that might be plugged or restricted? At idle is it dripping fuel from the main nozzles?
Check the base gasket where the carb meets the intake. Not sure about the Offy, but I know they don't seal well on an Edelbrock. Is the accelerator pump weight and ball check in correctly?
What is your float level set at? I don’t know about the 4100, but the 2100 will run without the top cover on. Maybe if the 4100 is the same, it would help with diagnostics?
I’ve double checked the gasket and from the witness marks it looks to be sealing correctly, I believe the ball check is in but will check.
I had a similar problem with the Holley version of this carburetor. Power valve was blown. I think I'd check that first to at least eliminate that possibilty before getting crazy with other options. These are a very basic carburetor and pretty trouble free.
These old Autolite carbs did seem to be "stone axe" simple. Any time I ever had one apart I was always amazed that they seemed to consist of only 6 or 7 parts. From years ago I remember an auto tech instructor mounting one of these carbs in a bench vise with the bowl cover removed. He filled the bowls with water and placed a big shop vac hose under the throttle plates to simulate manifold vacuum so we could watch the workings of the idle, main and accelerator pump circuits. I'm not so sure that he didn't also have one of the students working a mechanical fuel pump with the inlet hose submerged in a bucket of water, to make sure you understood how the needle and seat worked. When this instructor taught you something, he made sure it stuck with you! Thank you Sam. . . You left us way too soon!
Was the 352 running before rebuild ?? Did it have the Offy 360 intake on it and 4100 or other carb ?? Was this the cam shaft ?? Edelbrock Performer-Plus Camshaft Kit for Ford FE 352-428 V8 - Edelbrock, LLC. Shows 16" of vacuum .. does not say at what rpm My worn out stock 65 352 2 barrel with a 1969 390 2 barrel hi compression cam has around 18" of vacuum at idle A 4100 will not will not seal on an Edelbrock Performer intake, not sure what an Offy 360 carb flange looks like 4100 will not seal on all Ford factory intakes as well without the proper spacer When the engine is idling, slowly cover the front inlet where the choke is and see if the rpm goes up This will indicate a vacuum leak/ too much air to fuel Do you have or can borrow an carb that is known to run good to bolt on ?? Have you tried advancing the timing to see if the vacuum comes up ?? I have Performer 390 intake on my 352, I had to add a 1" 4 hole spacer on the intake so the 4100 worked The complete outside of the 4100 bottom has to seal
See the skinny edges on the outside of the carb, they must seal The triangle at the front of the carb must seal, it gives vacuum to the power valve
352 was running before rebuild but on the factory iron intake with a 2100, it was running rich as the choke wouldn’t come off. Cam is a Performer not the Plus I have a spacer and the gasket appears to show it’s fully sealing on all surfaces. I do have another carb but don’t want to take it off the Vette as I’m racing at the weekend. When I get a new vacuum gauge I’ll report back on the suggestions.
The ball is there but no weight. I did a lot of digging about that and apparently not all had the little cylindrical weight
Blowing air isnt always enough, you gotta use correct size drill bit to open those air bleeds out with all dirt.
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