Drifting a bit off the spares topic...
Carb cleaner, though you may not need to keep it on the boat
. Pulling the carb apart on board always feels like high risk unless you can get the OB into the cockpit
. And to delay needing the carb cleaner, I put seafoam in with each fill up, unless you are lucky enough to be where you can buy ethanol-free fuel
. The Seafoam still isn't a bad idea. I have also heard recommendations to use high-octane fuel. I try to stick with major brand gasoline from a gas station that does a brisk business. Valvtect fuel if I have a choice when buying
from a marina. No scientific basis for it though.