Mr Mark ,this is a old motor that has not been run in a long long time.
This reminds me when we bought our boat that wasn't run for years,
You have a list of things to do this is going to get long, you can do it,
remove all the old gas from everything,tank,fuel lines,carbs,
Remove the carbs and clean them like all the you tube videos.carb cleaning videos do.
Remove the old plugs and clean them its never the plugs, I know you bought new plugs,just making a point.
If one spark plug wire is bad replace them all.
This is another dirty carb post, and fuel system the gas from your fuel tank goes to a fuel water separator first, standard equipment now days,if you dont want fuel problems, and you need to add stabil 360 marine with vapor technology every time you add gas to the fuel tank, in the morning get your wrenches and remove the carbs, take them to a table/bench and start removing all the stuff that can be removed, push something through every hole/tube opening like the videos.Blow compressed air/carb cleaner through everything,welch plugs, needle valves,
Put the carbs back together, start your motor and report back with your findings .
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