Surging 392

Your photo's came through as text files, so we can't see them. Half plugged main jets would definitely do what you describe. 4.5 is reasonable on the PV.
 
Carb rebuilt, installed, new filter, and will not run. I have spark at each plug, timing is in the ball park (if not right where I left it), fuel in the bowls, and checked vacuum lines. It will start, but very rough and dies without holding down accelerator. My hunch is a big vacuum leak, but from where? Can you get a vacuum leak through the vacuum secondary's diaphragm? I'm grasping...
 
I can't answer your specific question, but your timing and ignition haven't changed. Only your carb. I still believe most if not all your issues were and continue to be housed in that device. I believe when you do get it squared away, you will see your vacuum at idle in the high teens and your engine being tolerant of a more reasonable amount of static timing advance.
 
I agree. I have been working on everything else for so long and it has needed attention from the beginning. With the issues found today I expect it to work. Just can’t think of what is wrong now.
 
Okay, metering block was still not flowing properly. Needs to be rebuilt. Couldn’t find parts readily available, but Summit Racing in Arlington had a new block in stock for $43.00. Installed the block and carb. Fired right up with 5 inches more vacuum than I ever had before. Still not as steady as I like, but 16 to 17 in Hg is great. Also, I can know get timing below 5* without dying. Set timing to 8* and drove like a new engine should. Still need some tuning, but very happy with results.

I will post additional results and pics later to hopefully make this useful for others.

Right now I’m taken by a couple of days of with family. Happy Thanksgiving everyone!
 
Hey, that's excellent progress! Use your vacuum gauge along with your ears to adjust your air idle mixture screws for an optimum ratio. And be sure the screws are the same number of turns out from seated on both sides. Happy Thanksgiving!
 
Glad to here it's fixed. There are just passages in a metering block, so they may have plugged with the same debris as the jets. Enjoy the family and your running Scout. Happy Thanksgiving.
 
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