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Tuning a Carter AFB 9501 for a stock 225
https://slantsix.org/forum/viewtopic.php?t=65663
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Author:  matv91 [ Sat Jan 09, 2021 10:51 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Only 16 inches of vacuum, that might be a clue, possible exhaust dilution at idle. Bad gasket at EGR valve or a bad seat in the EGR valve itself may not be ceiling. Turn the EGR valve up and pour water in to the seat see if it holds. Check gasket surfaces for flatness. Image

Author:  matv91 [ Sat Jan 09, 2021 11:01 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Bad gasket where that red arrows pointing, and if gasket is still good around the green line. Spraying carb cleaner from the outside may not detect this leak. This is a somewhat rare failure but I've had both the gasket fail and valve seat leak. Probably not your main problem but it is worth checking.Image

Author:  Reed [ Sat Jan 09, 2021 12:19 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

EGR was removed by a prior owner. There is a blockoff plate installed and I replaced that gasket when I got the truck five years ago. I will double check its integrity.

Author:  volaredon [ Sat Jan 09, 2021 1:23 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Quote:
Well, I spoke too soon. I took it for a test drive and it is doing the EXACT same thing that made me pull the BBD in the first place. Argh. I am now thinking it must be something ignition related because it just dies at a stop. Again, off idle is fine, but it won't idle below around 1000. :x
so the original carb is likely still allright?

Author:  Reed [ Sat Jan 09, 2021 1:43 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Quote:
Quote:
Well, I spoke too soon. I took it for a test drive and it is doing the EXACT same thing that made me pull the BBD in the first place. Argh. I am now thinking it must be something ignition related because it just dies at a stop. Again, off idle is fine, but it won't idle below around 1000. :x
so the original carb is likely still allright?
Probably. That carb ran fine for years and just suddenly stopped idling.

Last night I replaed the coil with an old MSD Blaster II coil and I replaced the cap, rotor, and wires. That seemed to help, but there are enough other electrical gremlins cropping up that I am afraid the truck is very close to not being a reliable daily driver. Time to park it and do a full resto, or figure out what to do.

Author:  kesteb [ Mon Jan 11, 2021 9:50 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

I suspect you still have a vacuum leak in the adapter stack.

Author:  matv91 [ Tue Jan 12, 2021 12:09 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Image

Author:  matv91 [ Tue Jan 12, 2021 12:12 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Image

Author:  matv91 [ Tue Jan 12, 2021 12:16 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Image

Author:  matv91 [ Tue Jan 12, 2021 12:18 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Image

Author:  matv91 [ Tue Jan 12, 2021 12:21 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Is this what your stack or adapter looks like?

Author:  volaredon [ Tue Jan 12, 2021 5:06 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

A big restrictor plate....

Author:  Reed [ Tue Jan 12, 2021 8:36 am ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

I will get some pictures. Give me a bit.

Author:  Reed [ Tue Jan 12, 2021 2:48 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

My adapter and gasket stack goes, from bottom to top,

1- intake
2- thick BBD gasket
3- phenolic heat shield specific to the BBD bolt pattern
4- gasket with the elongated bolt holes for the small and large 2bbl bolt patterns, but WITHOUT the holes for the small four barrel mounting pattern
5- two to four-barrel carb adapter with the two-barrel side down
6- four barrel squarebore carb gasket

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IMG_3611 SM.jpeg [ 87.69 KiB | Viewed 2972 times ]

Author:  Reed [ Tue Jan 12, 2021 2:49 pm ]
Post subject:  Re: Tuning a Carter AFB 9501 for a stock 225

Complete stack

Attachments:
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