Hard to say nothing may actually be wrong with it… I know my 96-97 40 horse Johnson, was a little tempermental to start, as it seems to me all carburated 2 stroke motors are, kind of gotta figure the personality of the motor and what it wants, usually I’d bring the idel lever up somewhere around midway and make sure the primer bulb is primed up properly, and Gas tank vent open, and would fire right off and run perfect for me. I later sold it to my cousin who has issues getting it to run and start, I know he’s learned her temperment now.
You may just need a little more time to get to know her, new plugs properly gapped shouldn’t hurt you any either.