Weird issue with AFB

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mbaird

mbaird

mbaird
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I picked up a Carter Competition 9635 SA the other day off CL . I went thru the carb and cleaned all the orifices , put it back to stock jetting ( assuming my web research was correct .. 95 primary/98 secondary and 7147 rods) and put it on my 360. Got it to idle fine but when I give it gas it dies then surges back to life over and over .
I checked the squirt shot and it look weak so I installed a new pump. Now squirt looks good .
started down the street and same thing…. When I hooked up my vacuum gauge to the carbs manifold port it read zero. So I switched to the ported one and got a reading of 5” at idle .
When I crack the throttle the reading on the manifold side jumps to normal but by then I am idling around 1600 rpm .
I did notice when setting up the carb that the primary throttle blades were a bit uneven so that when one side exposed the transfer port to square the other is closed ….
As for the surging I am using the same step up springs that I did with my 1406 so they shouldn’t be far off . Of course I cant get a good vacuum reading so its hard to know for sure .

Any thoughts ?
 
Barring a vacuum leak….. what’s the timing?

The pump shots linkage can be put into 1 of 3 slots, for now, if not done, the closest hole should be used.

What size squirter is in it now?
 
Vacuum for the dust should be 0 at idle but rise as the butterflys are opened.
 
Congrats on using the AFB, a great carb, Carter or Edel.

[1] If you have uneven t'slot showing at idle then the shaft is twisted or blade bent. The main air bleed & emulsion holes in the boosters change the jetting requirement. Eg, the 625 AVS carb has EXACTLTY the same size pri venturi & bore size but uses a 089 pri jet & a 66/55 met rod. So the first step is to ensure you have factory jetting.
[2] Something wrong with your measurements. If you got zero vacuum off a manifold port [ at idle? ] it means that port is blocked.....or the engine was not running.
[3] 5" of vac on the PVA port. This could be a few things. Long-ish duration cam that requires more idle air, blades open further, exposing PVA port. Insufficient idle timing.
[4] Need a complete run down on the combo to give more meaningful advice.
 
Ok … figured out the surge My brain was in Holley mode when I reassembled it and I stuck the 98s in the secondaries and the 94s in the primaries. Way lean .

I also figured out the lack of vacuum reading on the manifold port . Check this out ! They manufactured the body with 2 timed ports ! The orifice is above the T-Slot !
A251E76C-F4DE-4AB3-BD82-5BC8096F31FB.jpeg


4B57BACB-EC1D-4861-8FAB-283423EBA7BA.jpeg


1B0041C1-752B-40DE-965D-AA5E6E8A0AB8.jpeg
 
Here is the T-Slot to manifold port relationship on a 1406 Eddie . Notice how it is below the T-Slot ?
 
The exposed port in post #10 is for manifold VA because it is below the t/blades at idle.
The exposed port in post #7 is above the t/blades at idle & is for ported VA.
 
New and improved hole . Lol
D1E0E803-C0A4-4629-AD75-F4DE9D509EBB.jpeg

Bewy said:
The exposed port in post #10 is for manifold VA because it is below the t/blades at idle.
The exposed port in post #7 is above the t/blades at idle & is for ported VA.
Click to expand...

Yes … but both ports in pic #7 are above the T-Slot .
 
Well I guess you could partially close the choke on your next test drive.This will quickly tell you if its too lean, for whatever reason.
 
I drilled a new hole below the T-Slot but will have to plug the factory one . Still no accurate vacuum reading at idle.
But the car runs reaaly good know ! Super smooth off idle and cruise mode. If I mash it from a slow roll it will burn the tires even with the 2.76s I have in at . Cant wait to get the 46RH and 3.55s in it !
 
Sorry,
Not following this at all.
[1] Pic in post #10 shows a port below the blades [ at idle ]. This will supply manifold vacuum.
Why was it necessary to gouge the hole as in post #12?
[2] You can Tee into any man vac port, except PCV, to provide man vac for what ever accessory you want. So not understanding why a you had to drill a new port when you had one already?
[3] Are you using manifold VA?
 
Pic #10 is of a 1406 Eddie carb with correct placement of the orifice . The Carter 9635 has both vacuum port orifices above the T-Slot. I am sure this was a manufacturing error.
And yes I am planning on running manifold VA.
 
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