I used my Ariens snowblower twice today as we had steady snowfall. When I went to use it this evening, I topped up the gas, connected a power source, opened the choke and hit the power button. For more than 20 minutes the motor would not catch. Having thought I flooded it, I shovelled the snow manually for 10 minutes, came back to give it another try. Had it serviced this past fall and everything was working great. What am I doing wrong?