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Super six 8mpg!!!! :(
https://slantsix.org/forum/viewtopic.php?t=53259		 Page 2 of 2
Author:  Reed [ Sun Sep 08, 2013 7:35 pm ]
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V-8 bbd set up for a manual choke. Install a manual choke and be happy with it.
Author:  josekh7 [ Mon Sep 16, 2013 11:51 pm ]
Post subject: 
update i installed an electric choke which seems to help out alot my car no longer stalls on stop lights and i did a valve adjustment all my valves had almost no lash so i did 10int and 20 exhaust yet right after i adjusted my idle went up to low 900's she response way way better but my idle seems a bit too high the idling screw does not even touch anymore
Author:  pishta [ Tue Oct 01, 2013 4:35 pm ]
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Where are you located? I got a modern AL 2bbl holley slant retrofit carb, almost NOS with shelf wear only. Maybe another carb is needed? Im in Tustin. I was getting 5 mpg on a warm 351 Cleveland motor in my 57 ford, changed carbs and my mileage tripled with no performance loss.
Author:  Reed [ Tue Oct 01, 2013 5:52 pm ]
Post subject: 
Quote:
my idle seems a bit too high the idling screw does not even touch anymore
What is keeping the idle speed screw from resting on the stop? Do you have enough slack in the throttle cable? Is the choke adjusted properly so that the fast idle cam drop completely away from the fast idle speed screw?
Author:  pishta [ Tue Oct 01, 2013 7:31 pm ]
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idle set screw not touching anything tells me its a vacuum leak. The motor should choke off with idle screwed off. Are the butterflys seated properly on the shaft? Holly butterflys can not set right if you take them off during a rebuild.
Author:  Reed [ Tue Oct 01, 2013 10:27 pm ]
Post subject: 
This is a Carter BBD, not a Holley carburetor.

What kind of electric choke did you install? Was it a factory Super Six choke thermostat or was it the CarbsOnly electric choke retrofit? Did you modify the V-8 choke linkage piece or replace it with a slant six piece?
Author:  DusterIdiot [ Tue Oct 01, 2013 10:35 pm ]
Post subject:  How about?
Quote:
What is keeping the idle speed screw from resting on the stop?
If the idle screw is backed all the way out, and the throttle linkage is OK.
How many turns out from fully seated are the idle mix screws?

If all of the above checks out, I think vacc. leak is next on the list to find (need a can of brakeKleen or carb cleaner).

-D.Idiot
Author:  slantsik [ Wed Oct 02, 2013 12:24 am ]
Post subject: 
post deleted.
Author:  pishta [ Wed Oct 02, 2013 8:38 am ]
Post subject: 
Quote:
This is a Carter BBD, not a Holley carburetor.
I know, that's why I said Holley and not 'your'...;-)
Author:  Reed [ Wed Oct 02, 2013 9:15 am ]
Post subject: 
As has already been mentioned, if the engine is idling high and the curb idle speed screw is not touching anything, then the throttle is likely being held open either by the fast idle speed screw or the throttle cable. The throttle is easy to check and fix- just loosen the nut on the clamp for the throttle cable and see if the throttle closes all the way. If loosening the throttle cable doesn't allow the throttle to close, then you need to see why the fast idle screw is holding the throttle open.

The fast idle screw could be holding the throttle open for several reasons:
(1) the fast idle screw is simply screwed in too far and the curb idle screw is not screwed in far enough
(2) there is a problem with the choke linkage which is making the fast idle cam not move completely from out from under the fast idle speed screw, making the throttle be held open even when the engine is warmed up.

My guess is that the problem lies somewhere in the choke and choke linkage system. I suspect this because you are using a V-8 BBD that was at one point converter to be used with a manual choke and you have installed an electric choke. You need to verify that the electric choke you installed is the correct choke to use with the slant six and is not a v-8 choke or some other choke.

You also need to verify that you attached the choke linkage to the choke butterfly valve shaft correctly. There were v-8 and slant six specific pieces that attach to the end of the shaft and each is specific to the motor it was intended to be used on. Using a v-8 choke linkage on a slant six leads to the choke not working properly.

Additionally you need to verify that the fast idle linkage is adjusted properly. If the linkage is adjusted too short then the fast idle cam will not drop far enough to allow the fast idle screw to fall into the indentation of the cam and permit the throttle opening to be controlled by the curb idle speed screw.

So pictures of your current choke setup and choke linkage on each side of the carb would be very helpful at this point.

If all of the choke linkage is correct and adjusted correctly, the DI is spot on with saying you likely have a vacuum leak.
Author:  nzpete [ Wed Oct 02, 2013 12:39 pm ]
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a bit hard to tell from the photos, but I have real question marks over the accelerator plunger set up. Looks like the ratio/travel has been maxed out, and the washer on the top doesn't look like it has enough clearance.
There might be some fuel savings to be made here.
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