Bad news today - Bravo3 corrosion

[nickjh]

I had a call from Southwater marine today, boat was taken out the water for the annual service and antifoul. It appears that the anodes had corroded away and there is now corrosion in the leg, bearings etc. This apparently could have been made worse when I picked up a black bag earlier in the season, causing an overheat. This could cost around £2k or more to fix, which is a lot of money! Anyone had similar experiences? How much are these units to replace/rebuild typically?

Nick - very depressed.

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[andrewa]

Nick

New Bravo III around £3,200.00 + props at £500.00 a go. There is alot of talk on the web about this issue, the early Bravo III drives had the problem, though Mercruiser never admitted it according to the US sites and then did a 'modification' of the drive shafts around 2000/2001 I think. Mine has been hauled out and the anodes are 70% wasted after 6 months. My mechanic recommends you change them every 5 months to be safe. Also installation of another Mercathode is prudent mercruiser recommends this. My drive is a 2003 model and I have no corrosion after 7 months in the water and no second Mercathode. How many anodes have you got by the way?



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[duncan]

yes - see pictures on another thread or Boatones forum album.
I change my anodes every 4 months in Poole - despite having a mercathode and no shorepower anywhere around me - the BIII is a pretty light alloy.

My corrosion came about after new anodes were fitted by someone else - but not the Mercruiser ones! They looked fine - drive corroded. In a side by side comparison they weighed almost exactly twice the mercruised ones - different alloy and it wasn't up to it.This does save on anodes but ............./forums/images/icons/smile.gif
Got drive checked and told mechanically OK - it's the bearing carrier that can cause the probs and cost.
I then set to to make good and ended up back as new - in the water and enjoying the sunshine.
Alternatively I could have seeked redress and wasted the entire summer.


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[[2068]]

Unfortunately, you are not alone - this is a fairly well known problem:

http://www.findarticles.com/cf_dls/m0BQK/5_7/91085592/p1/article.jhtml

It's not the visible corrosion that kills you, but the design of the bearing carrier, which effectively dissolves because of the way it's bonded (not) to the rest of the unit.

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[Chris_B4]

Oh great, something else to worry about !

I had two new Bravo III X drives fitted last year and have noticed that the ram anodes do not seem to be wasting as quickly as the old ones did, in fact hardly at all

Duncan, you say that your anodes looked fine but the drive corroded, do you mean they looked like they were wasting OK or that they seemed to be lasting well. I figured that I should only really be worried if they dissapeared too quickly, what do you think ?

The drives came from a Mercruiser dealer so the anodes should be as recommended by the manufacturer

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[duncan]

in only a few weeks the drives corroded and the anodes did not - they all looked like new. They were keypart copies fitted by the marine engineers employed to change the drive oil and fit new anodes.
I would be worried if the anodes were not fizzing away quickly - yep it cost 90 quid a pop and I get through 2 1/2 sets a year but that's boating! (I have the luxury of both a pontoon berth and a yard cradle at whim).
As I said pics on Boatones album towards the end. Looked horrible but was all superficial according to the engineers (not the ones that ............../forums/images/icons/smile.gif)

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