Several points:
EBB, remembering that the motor is pulled once a year, and that I go on extended cruises, I question whether the lanolin will hold for the season, particularly on the lead edges of the prop, where the primary corrosive effect occurs. But it also occurs on the lower unit. (which is no problem with regard to painting using paint. It is the painting that is a pain in the propellor).
I have just replaced the zinc anode on the cavitation plate because the old one was approaching the end of its life. As for the wire, I will check continuity between the zinc plate and the electrical ground, although the problem occured the first year (2000), before I started painting the lower unit and the prop. Now the only problem is keeping the propellor painted without creating prop drag.
As for the type/brand/etc. of the prop, I am limited to the Yamaha reversing prop, which does not cavitate in reverse, as conventional props do. I would assume the metal is a mixture/compound of metallic elements, principally aluminum, but have no control over that. So, out goes a specialized/bronze prop - although I will enquire further about that and a plastic prop from Yamaha. I am not confident that a stainless prop will make any difference, other than lighten my wallet a lot more than buying several aluminum props.
As for the copper plate, I have checked that, and there does appear to be any corrosion. Only oxidation. However, when I had the corrosion problem (2000, before painting the prop), I had not installed the copper plate. The copper plate was installed in 2001 0r 2002. At the time of the motor installation, the electrical contact with water was both a) through the motor, and b) through the water intake valve. But that valve does not appear to be affected.
However, It may be noteworthy that, before I rehabed Solsken, the water intake covering plate had been totally eaten away over the prior 16 years of use with the prior Evinrude and McCullough motors). I don't recall there being a prop/lower unit corrosion problem, however.
As for the Garhouer unit, it really is a pain pulling the motor, taking off the wires, removing the exhaust tube, disconnecting the water barrier between the motor well housing and the lower unit, etc. Once a year is enough. The motor has to be in the well when the boat is in use, and I have no place to put it, other than in the well, when not in use. As for the lighter unit, I require the full 8hp. 6 hp is not enough - the reduced thrust (equal to a 6 hp) is what has raised this whole issue. In my case the motor is not only for getting into the slip, but for driving into tough seas and head winds (motor sailing), and getting to a destination faster when there is no wind.
So, back to plan A (Interlux paint), and plan B (plastic) with the possible addition of a coating of lanollin and see if it works for a full season. Any other ideas? but I will check the continuity of the wire, and the continuity between the battery ground and the zinc anode on the cavitation plate.
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