I’ve also been eye-balling my throttle linkages, poking around for causes for my idle stumble during the warm-up period in cold or warm weather. Throttle linkage shouldn’t be the cause of that symptom, but just looking things over. She purrs like a kitten and runs sweet when warmed up, but starts hard (catches, then stumbles and quits, and a quick throttle blip kills it), and then stumbles every 5-ish seconds during those first “4000 revolutions”. Didn’t used to do that, and after a couple of tune-ups last couple of springs (post winter) she runs as good or better than ever except for that initial start period.
I do now keep that right side idle adjust screw most of the way out. I used to adjust it back in to where its just almost touching the fuel lever on the TB, but I’ve started just leaving it out. Shouldnt’ make a difference, and makes it easier to do TB sync next time, but its a change. My eyes must have been deceiving me, but the other day i was looking over the left side idle adjust, looking to adjust the idle just a smidge higher, and after turning the screw in a little, could have sworn i saw some daylight between the adjustment screw and the lever….. how could that be? Looked around for linkage getting snagged somewhere (was idling just around 1000rpm), then finished double checking TB sync at idle and making just a slight adjustment on the air bypass screws, then looked again and the daylight i thought i had seen on that idle adjustment was gone. Hmm. Probably seeing things. Or was something actually hung up that i cleared from messing around down there (?). By that time, it was warmed up and idling and running fine, with the stumble gone.
To be clear, she’s well tuned in accordance with “decent tune-up”, and when warm is idling around 1150 (slightly high by choice), has the minor and typical stumble in the mid 3’s rpm, but otherwise runs/idles/rides sweet once warmed. Just that hard starting and stumble, where even “idle lever” all the way up may barely keep it from quitting for the few couple minutes.
Not sure I should bother with all my ramblings on this little issue of my persistent idle stumble during warm up, but maybe someone has some thoughts, and writing it down helps my brain sort through things, so here you go… some tedious reading material if you’re so inclined :-> cheers