Ignition off, throttle WOT, choke on.....rock the prop back and forth against the compression....it works the pump...if you have the chance to do it with the cowl off you will see it draw the fuel up the line to the carb...now here is the part that I have not perfected...if while you are rocking the prop you are listening you will hear a squishing when the fuel is finally drawn into the chamber around the rings....once you get there...choke off, throttle cracked, ignition on and give it a good stroke....I have seen guys with 50, 100 and 150cc engines turn on that ignition and get it on the first stroke each and every day....if you got the fuel up into the chamber the worst it might be is to pop and make you prop it another time or three....and yes, a perfectly leaned low end will be harder to draw up the fuel...my experience.