I had to do the same thing on the starters for my 6.354 Perkins. The starter and solenoid are right under a raw "saltwater" pipe inlet joint and a water outlet elbow and hose joint all serving the exhaust manifold!!
Crazy!! Where do you suppose the water goes when any of the four hose clamps leak?
I actually had plastic bags over them, until I figured out how to make a durable plastic shield.
ps (A small soft plastic painters pail cut in half lengthwise and trimmed to the right size makes an excellent drip shield.)