well, I just got my 550 running today, and I have the stock starter but it stays engaged well past the point required to start the thing. I would bet if the engine is firing/turning over fast enough to freewheel the starter instead of having the starter turning the engine, and it still isnt starting then there is a problem elsewhere...
although only owning a 440 13 years ago, riding it once, it died(and must have injested water), didnt put it away properly when it got home and the thing seized from sitting, and now finally getting the 550 running that hasnt ran since I have been in posession of it 3 year ago, I am far from an expert on the subject.
