When you reach under and open the choke does your fingers get wet with fuel? If not you are not getting enough prime. Maybe at that point open up the low needle a bit. Also I don't fly my gasser very often anymore so it sets for months at a time. When I do take it out I like to run it up for a minute or so and then let it sit with fresh gas in the carb for an hour or so to let the flexible parts in the carb soften up if they had gotten stiff. That first start is usually a bit more work and it transitions much better after letting it sit for a time. Something to consider if you completely drain your tank when done flying.