Try some high temp. silicon grease or waterproof high temp silicon grease.
this might be a good one, not sure though...
http://www.westmarine.com/1/1/465-dielectric-silicone-compound-from-ancor-marine.html
this might be a good one, not sure though...
http://www.westmarine.com/1/1/465-dielectric-silicone-compound-from-ancor-marine.html