Ok - here is the latest. After doing some additional reading, and against my initial judgement, I decided to go ahead and replace the batteries. I had to completely eliminate these as the issue, even though the old batteries were showing almost 100%. As it turns out, the old batteries were fine. (Just over 2 years old) I went ahead and left the new batteries installed.
To eliminate spark, and even though the old spark plugs looked visually fine, I went ahead and replaced all of the spark plugs. Made no difference.
My mind keeps going back to the fuel, even though there seems to be other electrical symptoms. The last thing that I did today is pull the air cleaner housing back, and went "Old school" with some starter fluid. The engine would start to catch when I sprayed the fluid while cranking. I didn't do enough to fully start the engine, but it did at least prove that there was some spark.
--> At no time did I get any sort of gas smell. I would think that, as much as I was cranking, that I would start to notice the smell of gas at some point. This makes me wonder if there is some sort of trouble with the fuel pump or something else in the fuel system. Short of the YDS, is there a relatively simple way to prove or disprove an issue with the fuel pump/system?
As I mentioned previously, I am not opposed to purchasing the YDS system from eBay - if/when I get clarification that it is useful for the newer boat generations, I will order ASAP.
