I have a 1.80 mounted inverted with a Cline Reg. There is no way to prime it so it can be back flipped. I close the throttle all the way with the throttle cut on the radio. This can also be done by pulling the trim all the way down. the starter will spin the motor with the throttle closed. There is no air to compress. Then once it is spinning open the throttle to the idle position. The started will be able to keep spinning it. Mine will fire right off. This takes an extra set of hands but there is always someone around anyway.

david