facel6

Yes, it's also my analysis
But don't forget that my car has a Duntov cam. This could explain the lower vacuum

Total advance is 36°

My ignition doesn't have a vacuum advance

GTOguy

With the engine idling and the screws all the way in, try pulling a vacuum line (if you have one) to induce a vacuum leak. See if it speeds up/smooths out. If so, you are too rich. Where is the float level set on your floats? A high float level can cause rich running in a lot of carb circuits.....it's the most important base setting of them all.

Frankie the Fink

36* is about right 'all in'. I was talking about the initial timing but I suspect that's not the issue based on your 'all in' number.

My '61 has a Duntov 097 cam and runs at 18 hg vacuum at idle.
I thought you had added a vac advance for some reason; apparently I was wrong.
What I was suggesting is that you block off ALL other vacuum 'draws' except for the vacuum gauge to eliminate those items a source of a leak..

Try Jeff's (GTOguy) test next.

facel6

the only possibility i have to make the test is to remove the plug on the rear base of the rear carburetor
This is where i'm measuring vacuum. I just replaced the plug with a take-off fitting (http:////www.parts123.com/corvettece...50e&ukey=42235)

I don't know where else i could get full vacuum measurement

What are the other vacuum "draws" that i should block off ?

facel6

Float level is set as explained in the WCFB manual. I have all the Carter tools requested to make the correct adjustments

olescarb

To facel 6 FYI the duration spring is missing on the accelerator pump in the picture you posted which would cause a hesitation problem on acceleration

henry @ oles carb

Frankie the Fink

You prob don't have any other vacuum draws...I was just trying to block off any potential vacuum leaks; with no C1 washer system, no vac advance then all of that is eliminated.

I see nothing wrong with the accelerator pump in your picture...the only spring involved is the one that sits down in the accelerator pump cylinder in the main body...

I don't know how the car is idling at this point. IMO until you find out why your vacuum is low it'll be hard to dial your carb in 100%.

tbarb

I don't know the WCFB carburetor like I know the AFB but me thinks there should be a override spring on the accelerator pump.

If you have a solid lifter Duntov 097 camshaft 14" vacuum sounds normal.

Try to find where the fuel is coming from at idle. You should be able to stall the engine turning the screws in to there seat.

facel6

Franky is right. The only spring is the one sitting in the cylinder under the pump

Where the fuel is coming from is a good question
Metering rods and jets are new (and correspond to the specs), but i had the same problem with the old one

Maybe the low speed jets ???

olescarb

[QUOTE=facel6;1593111052]Franky is right. The only spring is the one sitting in the cylinder under the pump

there are 2 different pumps used on Chevrolet wcfb Carter carbs the one in the picture needs a duration spring to function properly the other pump has a solid pump shaft and does not use a duration spring but it has a duration spring built onto the pump/metering rod shaft that goes thru the carb top.

the Walker brand kit # 15371c has the pump that uses a duration spring on the pump while kit # 15305 has the pump with a solid pump stem. Daytona parts also sells kits with both pump styles
Henry @ oles carb

Frankie the Fink

I don't know how to respond to this....the picture below is a freshly opened Daytona Parts kit with the accelerator pump still in its cardboard sleeve in the lower right along with the only spring involved. It's in my dual quads on the '61 I sold last month that runs like a banshee. No bog, no hesitation, just perfect acceleration

A vacuum reading of 14 at a curb idle is low IMO, my Duntov '61 easily held 18... However, I'm about out of ideas as to the nature of the rich mixture that the OP seems to have. I'm very suspicious of his car internals after seeing certain things. Might be time for a pro to go through hit

GTOguy

'Car' internals or 'carb' internals? FYI, I always soak leather accelerator pump pistons in ATF or Marvel Mystery Oil before the install.

olescarb

[QUOTE=Frankie the Fink;1593111639]I don't know how to respond to this....the picture below is a freshly opened Daytona Parts kit with the accelerator pump still in its cardboard sleeve in the lower right along with the only spring involved. It's in my dual quads on the '61 I sold last month that runs like a banshee. No bog, no hesitation, just perfect acceleration

Frankie if you look at the pump in your kit and compare it to the pump in the picture of the pump in the carb top you should notice that the pump in the Daytona parts kit has a solid pump stem while the one in the carb top has a pump stem that is movable thus uses a duration spring. The carb in the picture does not have a duration spring on the arm that actuates the pump and metering rods thus it has the correct pump but it needs a duration spring on the pump itself. If you used a solid pump without a duration spring on the pump arm the pump may bottom out in the pump bore causing throttle movement problems.

I think that most 2x4s used the solid pump while a single 4bbl used the pump with the duration spring but that is just from memory.

Henry @ oles carb

Frankie the Fink

Well - you've stimulated some memory cells....and you're correct. Good catch!
Based on what you found and the incorrectly installed throttle plates and whatever else may be lurking in that carb - I think the OP needs to send it out for a professional overhaul.

I wouldn't be surprised if there weren't mis-matched metering rods and/or jets causing some of his issues...

olescarb

I also now note that in the picture of your kit you can see the pump actuating arm with the duration spring the other style has no spring on it. I like Daytona parts kits but I still prefer the OEM needle and seat design that Walker offers.

Is it possible that the rich idle problem is because the carb does not have the bushing/tube that goes in the bowl vacuum passage that goes to the top for choke vacuum (was also there even on the carb without a choke on the top), if the gasket did not properly seal this passage it could suck fuel vapors from the fuel bowl and during corning it would suck raw fuel thru it.


Thanks Henry @ oles carb

Frankie the Fink

I put the WCFB "left turn stall" bushing in all my rebuilds - can't say I've had it affect curb idle though. As to the rebuild kits - I'm completely sold on the Daytona design specifically because of their modified float style.

A topic for another thread sometime...

facel6

maybe a spring is missing on the accelerator pump, but this is not the cause of my problem
This morning, i pulled a vacuum line to induce a vacuum leak and the engine slightly sped up .

facel6

I changed the metering rods and the jets.
I bought them from Chicago Corvette. Fore sure, a mismatch is always possible.
but this is unlikely because i had the same problem before changing the rods and the jets.

The only thing i didn't change (and check) are the low speed jets. Should be .031" (11-302S) according my documentation.

facel6

How can i check this ???

Frankie the Fink

You can see the bushing in this picture - there was a WCFB service bulletin about adding this bushing for stalling on left turns.

Its the red circled small vertical piece of pipe in the picture in the attachment