Treating drive corosion

I assume you have the correct anodes fitted. Whether to antifoul or not is a difficult question, but as you dry berth, I agree that it is not appropriate to antifoul.

There is light silicon spray (like WD40) that you could use, but this is not a permanent solution, and should be re-applied after every dunking.
 
IF by corrosion,do you mean minor pitting in the drive casing perhaps with the odd
bit of metal missing around exhaust,then it could be done in situ.All and any corrosion must be ground out/off and etching fluid applied to affected area to get back to bare metal.Fill any big pits.Then a primer followed by undercoat-topcoat-anti foul of your choice.
If really covered with corrosion best to remove leg at send it to leg rebuilder such as Coastal rides or IVSS,bit cheaper no VAT,(both in Kent) who will shot blast(or whatever) back to metal) replace any duff bits(water intakes etc etc) and give you back a like new leg.
 
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