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Bravo III corrosion

Posted: Thu Oct 15, 2020 11:18 am
by Blwalker105
This pic is our 2020 220S’s lower unit with only 50 hrs and 5.5 months in a southern Michigan lake. We sold a 1986 Cheetah to make room for this and its Alpha I drive looked immaculate after 36 yrs! What in the world will this thing look like on the same timeline?!

The Mercathode system indicated proper functioning all summer, but all the anodes on the lower unit show a fair amount of wear. Same lake, same lift, no other boats within 50 yds. It also annoys to see every picture of the Bravo III in the maintenance manual including a prop shaft anode, but my boat didn’t come with one.

She’s getting ready to go back to the dealer for storage, so hopefully they can shed some light on this problem area. One of many, I’m sorry to say.
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Re: Bravo III corrosion

Posted: Thu Oct 15, 2020 4:56 pm
by dustinm
I agree that looks terrible. Our family has had many Mercs over the years and never did we have one look like that.

Re: Bravo III corrosion

Posted: Thu Oct 15, 2020 5:49 pm
by XLI
Sorry to see that. If you purchased from the Cobalt dealer near Indy, same place I purchased mine, the prop zinc was in the case with all the stuff they gave me at closing. Was your boat wet all summer or on a lift?

Re: Bravo III corrosion

Posted: Thu Oct 15, 2020 6:51 pm
by Blwalker105
Thanks for the quick replies everyone. I just went back through all the closing items, and no prop shaft anodes were included.

Yes, it came from Pinecrest Marine in Fishers.

The boat was on a vertically-challenged lift, with the inboard prop and skeg mostly submerged all summer.

Re: Bravo III corrosion

Posted: Thu Oct 15, 2020 8:13 pm
by Big Block Power
Bummer forsure. I don't think the prop shaft anode is standard. I hate to say this but I've seen that before maybe not this soon but. Sucks report back to us what your dealer says.

Re: Bravo III corrosion

Posted: Fri Oct 16, 2020 11:13 am
by XLI
Blwalker105 wrote: Thu Oct 15, 2020 6:51 pm Thanks for the quick replies everyone. I just went back through all the closing items, and no prop shaft anodes were included.

Yes, it came from Pinecrest Marine in Fishers.

The boat was on a vertically-challenged lift, with the inboard prop and skeg mostly submerged all summer.
Interesting. There are two disc shaped anodes recessed under the horizontal surface above the props (cavitation plate). If that area wasn't submerged, you would have only had protection by the anodes at the base of the prop shaft which is a very small ring.

Re: Bravo III corrosion

Posted: Fri Oct 16, 2020 4:54 pm
by Blwalker105
Good Lord! So I should have kept my drive completely submerged to expose more anodes to the water? I am still learning here, so take my annoyance with a grain of salt.

Yes, I have both of the disc anodes and yes, they were probably out of the water for most of the boat's down-time on the lift.

But what is the purpose of the massively complex Mercathode system with its ever-glowing green eye and fine wire connections? Isn't that supposed to provide protection based on computer-modeled predictions of 90th percentile owner operations including mine? I can't recall if the Mercathode anode was under water during boat lift iterations, but I do remember seeing the ever present green eye glowing back at me when the boat was on its lift.

In my yard, as of today, it is off, as I would suppose it would be when the Mercathode anode is not exposed to water.

Concerning the Prop Shaft Anode, this is another major annoyance in which an American company chooses to pinch pennies in lieu of providing good, sound protection. How petty! If my dealer had informed me that I could have had added protection by adding this anode, I would have willingly spent the extra $90 after spending over $73K on my boat/trailer combination. Ultimately, it seems this anode would not have added any protection as it would have been high and dry for 95% of our boat's total time on the lift.

Like I said, the 36 yr-old Cheetah with an Alpha 1 drive is still pristine, and it spent its years in EXACTLY the same situation as the new 220S! Almost wish I had my plane back (N36LV), might have been less expensive to maintain!! Lol!!

Re: Bravo III corrosion

Posted: Fri Oct 16, 2020 5:55 pm
by XLI
No problem. I completely understand your frustration. I am no expert but here goes . . .

If just part or all of the prop and what's below that was submerged, your two stainless props present a decent hunk of more stable metal than your skeg area. Unfortunately the mercathode transmitter is mounted pretty much at the bottom of the transom at the base of the transom mounting bracket (if my diagram is correct) if that area wasn't submerged it would not be effective. I think it has to be submerged for a few hours to activate.

You did have a submerged anode. There is a very thin ring where the props mount to the hub. Basically where the inside 4 blade prop meets the black lower unit. No doubt the bullet shaped anode would have helped. Regardless, I am suprised at the corrosion. I would have thought Mercury's paint process would be more robust. The good news is a little brushing and some paint and your back in business. I'm in the Castleton area and have touch up paint & primer and even a paint marker that is easy to use in tight spaces if you want to borrow.

Re: Bravo III corrosion

Posted: Sat Oct 17, 2020 9:26 am
by akorcovelos
Wouldn’t this be under warranty on a brand new boat? Either way, corrosion that bad that quickly would make me look for something causing electrolysis. Do you have electricity on the dock?

Re: Bravo III corrosion

Posted: Sat Oct 17, 2020 4:17 pm
by Blwalker105
Yes, I have electricity on the dock, but before I go any further let me give special thanks to XLI for offering local help with my situation. I am hoping my dealer can resolve this issue, so I'll hope to not need your services as of now.

I have both a 12V, solar-regenerated, battery-powered lift motor for this boat's lift and a 120V lift motor for a pontoon boat on the same dock, but neither system was installed until mid-July. Before that, both lifts were entirely manual with no electricity to the dock. Again, the nearest other boat is 50 yds away.

All wiring for the 12V system is isolated from the aluminum dock, directly to the 12V battery, which resides in a plastic battery box on the wooden planking of the dock itself. The 120V pontoon lift is powered by a 50 ft, outdoor extension cord, which seems to be completely isolated from the dock.

Re: Bravo III corrosion

Posted: Sat Oct 17, 2020 5:12 pm
by Big Block Power
Blwalker105 wrote: Sat Oct 17, 2020 4:17 pm Yes, I have electricity on the dock, but before I go any further let me give special thanks to XLI for offering local help with my situation. I am hoping my dealer can resolve this issue, so I'll hope to not need your services as of now.

I have both a 12V, solar-regenerated, battery-powered lift motor for this boat's lift and a 120V lift motor for a pontoon boat on the same dock, but neither system was installed until mid-July. Before that, both lifts were entirely manual with no electricity to the dock. Again, the nearest other boat is 50 yds away.

All wiring for the 12V system is isolated from the aluminum dock, directly to the 12V battery, which resides in a plastic battery box on the wooden planking of the dock itself. The 120V pontoon lift is powered by a 50 ft, outdoor extension cord, which seems to be completely isolated from the dock.
That's awesome of another member. I take it you both boat on the same lake?
Paint it up and get it out of the water.