What is the true answer?

[john354]

My F 250 does not tilt all the way out of the water when raised. I have heard that , in that case , I should leave the engine down low enough so that the torque tab anode is in the water to prevent corrosion. So, is that the case and if so should I just leave the engine all the way down all the time? Thanks for any suggestions

[rodbolt17]

better yet.
tape off the lower portion that stays in the water when tilted up.
use the anti-fouling paint designed for Aluminum.
paint the portion that stays in the water.

[john354]

Thanks rodbolt. So with that aluminum paint applied, no need to have the engine low enough to cover the zinc torque tab?

[robert graham]

I believe the answer to your question is: tilt the motor all the way up, as much out of the water as possible. If some of the skeg, lower unit, prop remain in the water, just leave it that way. Your prop and prop shaft are both stainless steel and your skeg is painted aluminum to be pretty darn corrosion resistant. I'd worry more about marine growths, algae, barnacles and such growing down there than corrosion. Good Luck!

[axolotl98]

I believe the original question is more about galvanic erosion or electrolysis than simple salt water metal corrosion aka rust...

[robert graham]

Maybe bolt a small sacrificial anode to the bottom/side of your skeg that's in the water? That would work...

[john354]

Right. Corrosion is the worry. Guessing that bolting anything to the skeg would provide drag and maybe affect steering torque.

[Michael j]

Trim it up all the way.
There is a big bar zinc on the bottom of clamp brackets
(under power trim) make sure it's in good shape & it
should give you the protection.

[john354]

Yes, I saw that. Just not sure if the protection from that extends to the lower unit itself..otherwise why would the torque tab be zinc?

[99yam40]

Take Rodbolt's advice, and use the bottom paint