493 carburetor tuning question

I'll log in some time tommorrow to spend more time on what your notes.

Zachary Egnitz said

One thing that confused me was at one point my advance dropped significantly for no reason. I set it to
20 degrees and without changing anything ot moved to 9 degrees and yes my distributor was tight. I had to loosen it to reset it and as soon as I moved it the slightest bit timing jumped up to 30 degrees and I had to bring it back to 20. Not sure what the deal with that was but anyway here are my notes for the day...

Click to expand...

This sure sounds like something isn't right in the mechanical advance. I think it would be worthwhile looking at the advance mechanism. It sounds like there is slack in the advance springs.

Pink cam provides the one of the least amounts of initial pump shot. If nothing it else it will be useful for testing the gradual opening of the throttles from idle.

I do not worry much about how many turns in or out the idle mix screws are. Most important is they provide a control.