Thanks for your thoughts, @krab71 . Yes, I remember doing that too. I recall the 2 switches (one for each engine, I guess) overhead that I moved to the Start position. And a third overhead switch, which I believe is the start/ignition switch. But, all of this is new to me and I will try the startup again as carefully as I can.
My symptoms seem consistent with lack of fuel flow, so I will pay particular attention to that.