I recently bought a mid 80's towable backhoe with a Honda GX160 5.5hp, gut I bought it from said it hand's been started in 2+ years, based on depth of pine needles on tarp that was covering it, I think more likely 3-4 years
started 2nd pull, ran like a charm with old 10% ethanol fuel till it ran out
fresh fuel loosened crap in the fuel tank (float bowl & lines were run empty when last used)
carb immediately plugged up........ new carb was only $26