RE: Still need help with tuning
The idle check is a deal all to itself.
You want the engine warmed up completely. And you want the engine cleared out when you start the idle run, no matter how long you plan to let it idle. So.................
Let it run awhile when you got her cranked. If you crank her with the throttle just a couple-three clicks opened, then let her run like that as you pull the glow igniter and move around behind the prop. While you're doing that, you'll very probably hear the rpm pick up on it's own just a bit as the old oil gets pulled out of the bearings and nooks and crannies. By the time you're around back, you can advance the throttle to wide open. Let her run for a bit like that and........
you're cleared out any residual fuel that might cause your idle-up test to stumble
you've now got a warmed up engine
when you pull the throttle down to idle the engine will be coming down like it does in the air, cleared out and warm
NOW let her idle for your test. When you now hit the throttle to see if she'll stumble, you'll actually be testing from a condition that's more like flight conditions.