As left out in rain and now won' start why?

Sound like a rusted throttle cable. Make sure all the moving parts are moving. The other problem with things that sit, carburetor should be cleaned from shellac, from old gas

Water probably got into the high voltage wire to the spark plus(s) or the distributor. Open up what you can get closed again and dry out with a hair dryer or replace with new. Parts shouldn't be very expensive.