These old two-stroke Suzuki outboards are pretty rare nowadays. If it starts and shifts fine, it’s probably worth around $600 on the used market. That said, it really depends on the condition — stuff like the casing, cooling system, etc.
You ain't alone in this mess. My old Honda 150 carbureted outboard did the same crap. Cold starts were smooth, but after sitting on the water for 30+ minutes? Total nightmare. Figured out the fuel was either evaporating in the carbs or cooking into vapor lock from engine heat. Here's what worked...
Yeah, that does sound pretty frustrating — especially since it ran fine the first day and then just died the next. I'm not a mechanic, but from what you described, those sensor readings (the shift position switch and the negative throttle value) definitely seem a bit off.
