If it is not metal, go ahead and assume it's fucked. Whether it is dry rot or decomposition into mystery schmoo, what used to be components has likely turned into poison over time. Take it down to bits, replace functional things like seals. Yes, all of them. For metal parts the biggest time saver is ultrasonic cleaning. Do not simply fill an ultrasonic cleaner with gasoline or an otherwise flammable solvent! Ultrasonic vaporization is a real thing and even a small cleaner has enough energy stored in that gas to do some really bad shit. Gasoline and parts go into a sealed mason jar, that jar goes into the basket that goes into the water-filled machine. Then it is time to get the picks and magnifiers and make sure you're down to finish like paint or bare metal. Chinesium picks, some knipex dikes and pliers, and a mill file lets you work quickly and cheaply on the fly. Regardless of how much you spend or what wonder material they are, eventually the picks will get knackered. If it moves, it gets grease/oil. If it doesn't and it's bare (and is not a seal) it gets paint or some protectant. Note this is strictly mechanical, if you're talking about more than the spark plug wires (replace) electrical is beyond the purview of this sperg. You're going to want to use Ether (or whatever cucked starter fluid your country allows) on your first startup, and let it run at least a couple gallons of gasoline through it well before you shut it down the first time. My personal rule of thumb is at least 3 gallons, through at least 3 complete start/stop and thermal cycles. Short of this, or doing it wrong, is likely to result in gear that will never quite be the same. If your gear is NFG because of abuse and the actual structural bits of metal are knackered or warped it's likely to be irreparable or far more involved to make it right.
