Beginning to pull on my sparse hair. Fired it up again after fixing the float valve issue. Starts easy, even idles after a good warmup. BUT, exhaust for cylinders 1 & 4 are not heating up. I have great hot blue spark on them. Much better now that I've run an extra ground lead to the spark units (was reading 150 ohms from mounting stud to (-) terminal before and had weak yellow spark). Compression is not great on any cylinder, but is actually 10 psi better on the outside pair at 130, 120, 120, 130 when last checked. Have not balanced or messed with pilot jets yet (all set at 3 turns because the aircuts are disabled). Even with throttle open for ~5k RPM, the #1 stays ~60C, #4 ~90C while 2 & 3 go over 300C (read on outside of bend at head exit).
Ideas? Carbs have been off twice (fully cleaned 1st time, just looking for problems and fixing float issues 2nd), so I'm getting better at it. I heat the "isolators" with a heat gun until warm to the touch to make it easier on them and me. Spray of brake cleaner around carbs and isolators yields no change in idle. Full airbox and filter. New plugs. 5K ohm plug caps, new plug wires, coils ~11K ohms secondary, 2.5 ohms primary. Pulled #1 cap while idling and no change.