Solution to my running rich problems
 

I just wanted to post to celebrate, gloat and inform anyone else that may be having a similar problem.

My car is kind of a Heinz 57 (long story), a 79 engine with 81 intake and carburetor. A previous owner stripped the carb. The entire time I've had the car, it has surged when coasting, had trouble starting warm, and overall has had symptoms of running rich.

I initially thought it was excessive fuel pressure, as the bowls would overfill if you set the dime-store Mr. Gasket FPR above 1.5 psi. I plumbed in a good quality pressure gauge, and the regulator was strangely dead accurate. I managed to fix the overfilling by cleaning the needle and seats and whacking the banjos with a mallet.

I finally figured out the previous owner had filled in the ports that connect to the air horn's small air bleed. Drilled out the sealant he used, and drove the heck out of it until it sucked anything that fell in through.

Now it runs smoother, coasts smoother, shifts smoother, just runs better overall.

Tl;Dr: If you are running rich and have tried everything else, check that the 2 ports between the primary and secondary barrels on either side of the air filter stud are not blocked.

Nice bit of detective work! Thanks for sharing.

Stu Aull
80 GS
Alaska