I watched a couple of guys get 2 of these running at the same time, both of which had sat for at least 10 years. they cranked but would not start. They would start on starter fluid. both had partial tanks of gas. Ethanol had swollen the fuel pump rubber bits up big and puffy. Iirc, they replaced both pumps, added 5 gallons of fresh gas to each, and started them up. I would have tried to drain the tanks but they didn’t do that.
ill add another vote for startron - saw it used on a C2 which had all kinds of fuel problems and it did make a difference - helped.
with 5 years, you could get lucky! Could start and go!