Weird Six pack carburetor troubles!

[Coronet guy]

I’m having trouble with my 440 six pack system. I had it rebuilt this year but now I’m having trouble with cylinders 1,2,3and 4 fouling the plugs. This is happening with in approximately 6 to 10 miles. The other plugs are still like new. I pulled all of the carbs off and I took the bowl off the front carb, there wasn’t any fuel in the bowl. The other two were right where they are supposed to be. When I changed spark plugs, it fires right up and works perfectly, but after about 10 miles or so, it starts backfiring, loosing power and runs terrible. I was suspicious that it was trouble with the front carb,so I took the bowl off to check the needle/ seat. They seem to be holding fine, so I removed the float,and stuck it in a dish with gas in it to see if it possibly was cracked or a hole in it. I left it in for about two hours and it seems to be fine, I submerged it several times and watched for bubbles but I didn’t notice any. Does anyone have any advice or information as to what could possibly be wrong with this situation? Any help would be greatly appreciated.

 

[AR67GTX]

It’s all guess work but sounds suspiciously like one of the carbs (front one it sounds like) is gradually overfilling the bowl and flooding out the boosters after a few miles. Or the fact that the bowl is empty when you check it could be due to an internal leak through the metering plate - warped plate or something like that.

 

[DanielSlocum]

It sounds like the front carb is leaking fuel into the intake for some reason. Thus your plugs get fouled and the front bowl empties after shutting the engine off.
Not sure how that could happen;perhaps base plate screws are loose causing gasket leak,another gasket leaking,something cracked or warped?