32mm ADFA Jetting

[Schnauzer]

The air correction jets on my carb are 170 for the primary and 185 for the secondary. Does that seem about right? I have converted this 76 to single points and have the timing at 10 BTDC. It idles good and pulls great in the mid to upper RPM ranges but stumbles and surges just off idle. Seems to be lean at that point. Adjustment needle likes to be WAY OUT. Accelerator pump is working fine. Idle solenoid clicks but not very hard. Not with a snap. Any thoughts? Forgot. Dwell is about 50 degrees.

Thanks for your help,

Jim

[So Cal Mark]

sounds like it needs a larger idle jet

[sptcoupe]

The air corrector only begins working when you are at or near full throttle and in the upper rpm ranges. It works directly with the emulsion tube and the main jet, so if it is runing well at the mid and highgy rpm ranges, it is not the air corrector. At idle and up to the midranges, the idle jet is the main gas meter. Mark is right, try a larger idle jet, but before you do that, make sure the idle mixture is correct. Too lean or too rich an idle mixture will give you a stumble coming off idle and up to about 1800 rpms. It could also be that the idle jet is too big (rich), too, but start by making sure the mixture is correct. It also might be a weak fuel pump that doesn't start to pump enough fuel until you are at higher rpms. I always use an electric pump with a fuel pressure regulator to eliminate this very common and hard to diagnose cause of tractibility problems. That said, my bet is the idle jet and/or idle mixture.

[Schnauzer]

Thanks for the replies guys. What a can of worms. I am certain that this carb has been apart before. I have no way of telling if the mains and air correction jets are in the proper spots (primary & secondard). The idle jet is a #50. The mains are #145 & #120. Does a jetting chart exist? What is the collective experience here for a starting or common set up? Please get me started. Knowing these components have been out previously I have no way of knowing if they are in their proper locations and combinations.

I may have found an other part of the equation. Very weak spark which might account for some of the stumble. The primary resistance on the coil is 3.45 ohms and the secondary is open. My Spider was equiped with an external ballast resister from the factory. What is the coil of choice for my car with an internal ballast? Any Napa or Bosch numbers. IAP lists a Bosch "Blue Coil" but no # other than their internal stock number.

Any help on jet locations and a coil would really help me out. Thanks.

Jim

[So Cal Mark]

main jet------------1.25
sec main jet--------1.40
idle jet-------------.50
sec idle jet--------.60
emulsion tube-----f74 both pri and sec
air jet 1.85 pri, 1.70 sec

the only difference on a car built to Calif specs is the pri air jet is 1.80

This should be a starting point for you, altitude can make a big difference

[joelbert2k]

Mark,
You mention that altitude can change things on the jetting.
What changes should I make when I put my 32ADFA on my stock 2ltr.
I live at 5000ft.
Joel

[So Cal Mark]

Joel
I'd use larger air jets at 5000 ft. It will take some experimentation, but I'd go one size larger and check the mixture

[joelbert2k]

Thanks Mark.
I'll give that a try. I couldn't remember which way to go.
At least the air jets are easy to switch out.
Joel

[Schnauzer]

Thanks Mark, big time. This helps tremendously.