Reply to "Call for help 1 hour North of the SanFrancisco Bay Area (Santa Rosa)"

The Webers "TEND" to darken the plugs at idle and it is difficult to lean the ratio at idle without making it backfire through the exhaust.

In the early days I would blow muffler baffles out as a result.

I really am convinced that it is a function of an individual runner manifold that actually has all of the butterflies closed and you are really ideling on the idle screw adjustment.

The changes are so small at idle, just the differences in machining tolerances on items like the pitch of the threads changes mixture volume and sometimes mixture strength.

Just something that you need to come to a conclusion on after you are completely successful at it or only partially successful.

Read your plugs. They will tell you what is going on now and if you are really good will show you the different levels you went through such as idle, WOT, and sometimes you can read multiple runs.