I have a similar question: what do you do with the motor when you're on an extended cruise and can't flush it out each time you dock or anchor? Is it better to leave in immersed or pull it up?
I raise my twin 45's too. Where I keep the boat (at my pier) I don't have water yet and when they come out of the water, lots of nasty salt water :smilep comes out and drains. I flush them well at the end of the season but in betwixt, they are salty....
Interesting; I leave them in the water. I don't want that salt to dry inside my engine and figure that as long as they remain wet inside, I have a better chance to flush them clean.
Also - while I do trailer with them up, I wish that I had ground clearance to have them down because there clearly - in my opinion - has to be much more stress on the transom in the up position. Imagine holding a bucket of water at your side as opposed to your arm stretched out away from your body...
I tilt the motor out of the water in our home port so the gunk won't grow on it. We only moor the boat in the Spring and Summer, so freezing is not a concern. I do know that if there is a chance of a freeze, then down is the only way.
At most of the CB gatherings, however, there is no choice but to leave the motor down. Otherwise, the dock ain't big enough to hold us all.
I leave mine down. This keeps the salt in solution.
As mentioned above the air evaporates the water leaving salt deposits behind.
I check or change my zinc anodes every year. If they are starting to pit it is time to replace them. Sometimes I go a bit longer.... hate to quit fishing you know... but I try to start each season with good zincs on both motors.
A good long flush with the flush bag right after I pull it out of the water and it is ready for a soap and water bath.
I have neglected the wax job this year and need to talk Catman into helping me put the luster back on the old girl. Heck, I might even have to put the granite sculpture back on the table and bring out a martini shaker....
We bring our engines up when in a marina -- don't want electrolysis. We also bring them up when there's a threat of electrical storms - don't want those metal conductors in the water. Anchored in shoal water, with tides and a lot of swinging, we have them up so they don't 'go bump in the night' with anything unexpected underwater.