Reducing weather sensitivity of Carb setting?

[Joisey]

Is it possible since this saw has some hours on it, that the crank seals are sucking air when the temps are low, changing your idle mix?

 

[J D]

If it's 25 psi you can. Alot of these newer China carbs I getting excessive popoff readings

I think you may be referring to the spring pressure on the metering valve being too great... this can affect the metering & will also cause pop off to be higher (sometimes a fix for low
Pop off pressure is to replace or very slightly stretch the spring).
Pop off is purely a measure of the metering valves ability to resist opening under excessive fuel pressure. So long as the spring isn't to stiff for the metering to function correctly there is no reading that's too high (although I still wouldn't want to put more than 25psi on it).
Think of it like a faucet, it doesn't matter how much pressure it will withstand as long as it's more than the system it's installed on & it opens & closes as it should.

Yep, and how does the metering diaphragm move?

The diaphragm is drawn in by the vacuum created in the chamber as fuel is sucked out through the jets by the venturi vacuum.
If the diaphragm isn't opening the metering valve properly it may be due to the spring but is far more likely to be the result of a stiff diaphragm or the gap (metering height) being incorrectly set

 

[J D]

Is it possible since this saw has some hours on it, that the crank seals are sucking air when the temps are low, changing your idle mix?

I've seen air leaks that only show up when the saw is warm... PITA to diagnose!

 

[maowwg]

Just a follow up. I richened and up the low end screw until it puked and then increased the idle until it ran consistently. It seems to like that setting. Which is weird but whatever...more fuel more air - similar ratio, but fewer fine tune adjustments.