I know it's not kosher to start an engine from cold this way but it works for me and that is: Leave the primer locked. Throttle full then return to start up position. Turn over the engine and if it doesn't start on the first two complete turns, briskly advance the throttle to full then back to start up position. If it doesn't start after another two revolutions, repeat. If it doesn't start after that, it's time to rethink since continuing to pump the throttle may result in a fire! Personally, I never ever use the primer.