piston port engines in general are harder to start. especially with the bn carbs. its got to be something simple thats getting overlooked. how old is the fuel your using? what fuel mixture are you using? the pump gas today absolutely sucks! if its more than 30-45 days old then get new. and run 45to1 oil mix. also, what are the screws set to? hard to tell by looking at your pictures but it looks like there may be a small nick in your pulser coil insulation. its the top front coil. possilby couldve turned one of the flywheel puller bolts in too much and made contact with the coil, ive done this and mine wouldnt start either and it is a reed engne. while you have the flywheel off, take a look at the magnets and also the inside where it is against the crank snout. take the return line off at the tank and see if fuel pumps back in when you turn the engine over. when you poured gas down the cylinder its possible you have flooded it out. the piston port engines dont have reed valves to help control and help the air and fuel mix. also check the exhaust hose on the other side of the waterbox where it exits the hull. that hose has an almost 180 degree bend in it and ive seen them become kinked shut which wont allow the exhaust to breathe and it wont start.
if you have compression, and you have spark which according to your posts, you have both. it has to be a fuel delivery issue or a sheared flywheel key, which you wouldve seen when you removed the flywheel. you can figure this out without sending your ski to someone else to get running for you. besides, when you do figure it out and get it started again on your own, you'll feel that much better. There is also a much better 550 following on pwctoday.com than here. if i was closer id say bring it over and i would help you get it going again.