rebuilt the kiehin fully, got it running top notch all the time with one exception. on cold starts below -10c its starts like normal, ramps up like it should then in 5-10 seconds just drops out to full stall, not even a stumble. then second start choke works perfect. at -20c it does the ramp up and stall twice then fine. next time it hits that cold I'm gonna get the wife to start it and see if the butterfly is opening when this happens, i suspect it is. anyone else experience this or fix such an issue in the past? I've rebuilt the unloader and replaced the choke pull diaphragm/pot. and have the tab dialed in once running it does it's steps and works perfect. my best guess at this time is a solenoid might be firing when it shouldn't in the black box. it's definitely not leaking vacuum and is tuned and timed with exhaust sniffer and timing light as it should be. it just turned 135000 km so it's definitely done a lot of sitting in its life I got it from the original owner who drove it to church on sundays and groceries until 2018. during -9 or warmer this doesn't happen just starts first turn as it should. i'm almost sure the choke pull is doing something funky through a solenoid I'll update I get eyes on it in those temps. I haven't changed or tested the air intake temp sensor but I'm not sure it has any input into this circuit/action but I may be wrong.