I love replacement parts...
Put a new larger accelerator pump and squirter in. It worked way better but still had the stutter. So I put the next bigger size in, a 40. 40 requires the hollow screw, and it comes with it. Put it in and the squirter doesn't squirt. Wouldn't start, accelerator pump is hard as a rock. I had changed the pump cam so thought maybe I screwed something up. Took it apart, and realized that the screw for the squirter was too long and held the needle under the squirter nozzle down. In the process, I learned that my #40 nozzles were dropped in transport, both had the brass tubes pinched at the end. So I would have been very lean on one half had I not noticed that. So I put it back together with another squirter, drove it down the road and it whistled at part-throttle. What the heck? I tried a few things and realized it also whistled slightly with the engine off. Turned out at some stage I got about an 1/8" long tear in the pump diaphragm. That's not all, though. I also got a slight tear in the rubber check valve diaphragm. Probably from the high pressure when that nozzle screw was preventing flow.
More parts on the way. Getting closer, and learning a ton about performance carburetor tuning.
I looked at the carburetor squirter on the Holley Street Avenger on my 62. It had an off-idle stumble slightly. Turned out it had a bad gasket between the nozzle and carb body from the factory, so it was pouring fuel through there. Boy, throttle response improved when I fixed that!
... I'll make a stab at it.
