Does anyone have advice on identifying starting issues with M6Di.  My 2022 Response occasionally fails to start.  The motor turns over and sort of stumbles and fails to fire.  When I hit the starter button again the motor winds over a for a slightly longer period of time and then usually starts.  Sometimes it is like it has flooded and will run rough for a couple of seconds and then be fine.  This happens around one start in thirty and today it was the worst it has ever been.  We waited a few minutes, turned the isolator off and back on and it started first attempt with no issues.  We had skied the course for a couple of hours before this happened and boat was great.  Am trying to determine whether there is a likely fuel pump or advance issue or whether something electrical with the isolator switch or failing battery could be the cause.  I opened the fuel cap today and there was a big suction of air into the tank like it had pressurised as fuel was being used.  When the motor winds over there sounds to be heaps of grunt from the twin batteries.  I am getting the batteries tested tomorrow, just can't help wondering whether this sounds more like a fuel or air cause.  Would definitely appreciate any advice you could share.

Well I got her running…..
Something that will not happen again, doubt for a long time. The screws holding the rotor under the distributor cap had backed out which allowed the cap to rotate it still provide spark just not at the right time.
A new cap and rotor and she is praying like a kitten once again .

Glad to hear that you are OK.  Hopefully you will recover fully.  Welcome to the crew!

Did this happen in Chaing Mai (เชียงใหม่), or are you somewhere else?

I would start with the basic preventative maintenance items like you said. 
cap, rotor, plugs, plug wires, and fuel filter. 
For the engine temp, make sure the impeller is good. Also, clean the screen on the oil cooler heat exchanger. What was the temperature displayed on the screen? 
 

If the impeller was used for 30 hours and then sat in the garage for 2 years, you may want to remove the cover and inspect for broken / missing vanes.