I say rebuild the carbs with OEM parts (preferrably) and make sure the engine in straight up and down when you prime the bulb and try to start it. That's made a big difference in the starting of my 1978 200hp Black max merc. Is the fuel tank new too or, if old, have you checked to see how dirty...
I have a 1978 Black Max 200hp 2 stroke and live at 7000'. I just got it and have only had it out twice before having engine issues. I have made a lot of repairs and deferred maintenance and will take it out this weekend to test it. High hopes it will finally run well. I'm also interested in any...