[QUOTE=pelican;240684 . . . water in the bilge,sea water,boat's covered - heat builds up quickly...water evaporates,yes ?
salt is left behind,salt wicks moisture - it has a corroding effect and a prying effect

moisture rises too... [/QUOTE]

Good points about the warm, damp bilge/engine compartment!

My friend that bought the Moesly 21 "Unohu" I/O new in 1965 and ran it for 27 years, literally wearing out 3 different engines and drives, was fanatical about keeping the bilge dry! He wasn't satisfied with the main bilge pump because it always left a little water in the bilge. His concern was that windage off the flywheel would spray any bilge water all over the engine so he installed a second tiny pump with a manual switch. Claimed it left the bilge just barely damp! I followed him all over the Bahamas on a half dozen trips, and I noticed that EVERY TIME he put the boat up on plane, being a very methodical engineer, he would turn on that pump and look back over the side to see if it spit out any water!

Ideally you'd like to have a solenoid that is 100% airtight, but if it's the type that's integral with the starter that mechanically actuates the Bendix gear like a Chrysler or some GM types, it definitely won't be airtight, even if ignition protected! And although a wiper-type contact is a good idea, I've never seen a starter solenoid made like that.

Regarding sprays, how do you like Boeshield? I like the idea of the waxy protective coating it leaves, although I don't know how good it is at displacing existing moisture.

nope ! don't like boeshield - I use what I recommend

in my sea craft - I slid a whale submersible pump way back under the motor - they're great - low profile and they'll fit under the motor.this keeps water out of the bilge...

this is the whale pump - highly recommend these !

I've used these a lot on customer's boats - they're easy to mount - they swing around for mounting and the water outlet - fully automatic too

All good points...normally when I am done boating for the day the boat gets a good rinse,motor flushed and the bilge drained...then i try to leave the cover open until the motor cools down. Now I will have to add the spray to my list :D

Ter #1, Señor Pelicano is right. Hold out and get the Lear Research "Corrosion Block" - it is the best. It is a little hard to find but worth the search. It comes in a cool rustproof aluminum can, like a little fire extinguisher. The problem is it only costs $4.00 less than the fire extinguisher, but it's still worth it.

Ter#3

Use either "Corrosion Block", "Corrosion X" or "Fluid Film". But for 1st use, use them AFTER you use an electrical contact cleaner.