This is a PA40UL, running APC 11.5 x 4 prop. I have CF 3-blades from Brian Eather but don't want to risk them on the pavement at our field. Motor got 2 hours of break-in on stand, now has about another 30 minutes in the air so still pretty tight. Started literally on first flip on test stand, then about 10 more during break-in. I am still figuring out how to reliably start it inverted in the model with it on its wheels. Need to get a filter or some stocking fabric on it.
Burp - have someone hold the airplane inverted, dribble fuel into the venturi, tilt nose up, rock prop back and forth, rotate airplane wings vertical, rock some more, until it feels "loose". Then hold airplane inverted, attach battery and back-bump up against compression. It may spit and pop the first time, repeat until you get a full speedup and then rundown.I habitually wait do this three times - fuel in venturi, back-bump, speed up and run down. When done, repeat back-bumps until you just get pops - this ensures that you have gotten all the stray fuel out of the engine.
Cold - pull through compression 3 times with your finger over the venturi, remove finger and flip through immediately a few times to suck raw fuel into engine and aerate the charge, attach battery, back-bump up against compression. If it doesn't go, repeat, the problem is not enough fuel.
Hot - pull through compression once, attach battery, back-bump. If it bursts but then quits (meaning you had enough choke but not enough fuel in the line), then you might have an issue because of shrinky piston syndrome. If so, then remove the battery, flip through compression forward about 20 times, attach battery, back-bump up against compression.
"lukewarm" - you have to choke it a few pulls, which may cause shrinky piston syndrome, because you have to choke it a few times, and cold fuel on the underside of the piston crown will shrink it. Hot, you don't want to choke it to the point you get raw fuel in the engine, just enough to make sure the fuel is in the line. This is the most difficult condition to get it started, solution is as above, remove the battery and flip it through forward a bunch of times.
DO NOT ever flip it through compression with the battery attached like a McCoy or ST, in either direction, unless you want a ride in an ambulance or enjoy the sight of blood. It's not at all nasty to handle but you just don't want to do that, ever, to one of these engines. Back-bump by winding it forward against compression, the vigorously flinging it backwards, but DO NOT flip it through compression, your finger should be far away from it when it hits compression and fires.
With the APC, feel free to sand the TE of the prop flat with 240 grit sandpaper until you can safely flip it forward through compression (with the BATTERY OFF) to aerate the charge. Unless, again, you enjoy the sight of blood, in which case you can leave it as it comes, sharp as a straight razor with a wire edge.
Brett