An upright engine is more tolerant of an overprime and idle mix settings. With an inverted engine you have to learn how to get fuel to flow uphill from the spray bar and through the crankshaft port. But also you can't overdo how much you prime or you can get a hydraulic lock which could cause serious damage. With the idle mix you need to set it more carefully to where it's just barely on the rich side. Once you figure out the priming they'll start one flick just as easily as upright. If you must use an electric starter it's wise to flick it over by hand 5 or 6 times after priming to make sure it's not flooded. If you do this then always treat it as though the glow heater is working because one day it will be