I was having trouble starting mine before the first flight of the day. Took something like over 60 flips to get it to pop with the choke on. I think it just doesn't have a strong fuel draw on choke. I have a fueling "T" in the line from the tank to the carb. I now fuel the tank until it spills a little bit out of the vent. Without removing the fueling line, I close the choke and with the ignition off, flip the prop 4-5 times. Disconnect the fueling line, turn the ignition on and flip with the choke on. It usually pops in a few flips. open the choke and its starts withing 4-5 flips. Nice thing is it sits sometimes over an hour between flights....it will usually start with one flip...no choke. Great little engine! I think my starting problem was that when I removed the fueling line I introduced air into the line. By choking with the fueling line still connected seems to be a simple fix. Would be interesting to see if this works for you too.