The first start of the day
I've noticed this behavior dozens of times over the last year and am wondering what the cause is: Starting my OS AX engines for the first time on some days, the engine will start, but it will not take throttle at all and will falter or stall with the glow plug driver still connected. (It will run at idle or low throttle but you can tell it is lean.) Choke the carb with your finger just a fraction of a second and it enrichens and runs normally and can immediately take a more wide open throttle. What causes the "first start lean syndrome"? Note that I rarely touch my needle valves unless the temperature has changed or if I am tapping a new gallon of fuel. By the way, this syndrome never happens on later flights, only on the first flight of the day. I have never noticed any bubbles or air in the lines when having this situation. Any ideas on why a quick choke while it is running clears up the problem?