I have gotten to be pretty fluent in jet tuning with Bing carbs on 2 strokes and I don’t want to apply the wrong info to my 4 stroke. I have an HKS 700E (don’s top reading if you’re a 912 person) and I am having EGT issues. I only have 6 hours on the engine and the highest OAT I have operated in so far was mid 40s. At that temp I had a hot spot between 4200-4900 where EGT would hit limits if allowed. Today I went to fly and it was 28f, the coldest yet by about 10 degrees. At full throttle my take off run only produced 5600 RPM and 1390 EGT (limit is 1400), normally I hit 5900-6000. The engine did not produce proper power and almost exceeded limits.

In my head it all points to higher air density leading to a leaner mixture and I need a bigger main jet. But I can not find info on tuning Bing carbs on 4 strokes. It seems to be set it and forget it because of the constant velocity system. Anyone else braving the cold temps and experience anything similar? Am I misdiagnosing the issue? Does prop loading affect 4 strokes the way it does 2 strokes, similar, different, at all? On my Lycoming loading the prop leads to higher CHTs which ultimately lead to higher EGTs, but it takes a minute.

input and thoughts, please.