you should put some Di-Electric Grease on your plug and inside the boot. this will keep water out.
Definately do this, also put it in ANY electrical connection you can find. Water can still get in your drain tube some how, the best "plug" for that is the clamp bolt on the rear output shaft, perfect fit almost as if honda designed it that way... I also ran a bead of silicone around the inner lip of my airbox cover and let it dry before putting it back on to form a gasket. Seal up your pullstarter to. That should be about all that is needed.you should put some Di-Electric Grease on your plug and inside the boot. this will keep water out.