Southern California - what is the real, actual, true story on Bravo III maintenance.


L

luriesd

Member
Good afternoon! I just purchased a 2000 Formula 280. Twin Merc 350 with Bravo III. It is slipped in Los Angeles, in saltwater, full time. Has about 475 hours now, and a freshwater flush system (aftermarket) that the prior owner claims he used religiously.

The survey (including an engine mechanic who went pretty deep into the 350s) went well, but he said the "annual" maintenance was due on the IIIs. He showed me some rusting on hose clamps, etc. Bellows were tender and supple and looked good. They DEFINITELY needed to be painted. The prior owner had them maintained every 100 hours.

I have had several mechanics here in Southern CA give me WILDLY different ideas on what annual preventative maintenance should consist of (and cost). From (lube, inspect and replace bellows as needed, and torque steering, change anodes) all the way to: (Those are nightmare drives, how dare you keep them in salt water, it will be 2500 per side every year for a new gimbal bearing and everything else).

Can someone give me the skinny? I want to be proactive, and take good care of her, but not get ripped off.

thanks!

Steve
 
I think the best thing is to talk to and get information from people who actually run /keep their outdrives in salt water. (like me . . . )

For the Bravo 3 drives. . .

The problem with the Bravo drives is that there is too much stainless steel (propellers, prop shafts, etc) for the amount of aluminum (casings/housings). Different metals placed in water experience electrolysis which is the transfer of electrons from the 'weak' metals to the 'stronger' metals . . . resulting in galvanic corrosion. So the weaker metals depletes one molecule at a time . . . since much of the outdrive housing and transom mounting is aluminum, they yield material to the stronger metals in the outdrive (steel/Stainless steel).

Dual prop outdrives experience this . . . regardless of brand. The critical aspect is how the drive deals with the depletion of material from the weaker metals. The solution has been and continues to be the attachment of a weaker metal to the outdrive, making the aluminum housing no longer the weakest metal.

The early Bravo 3 drives did not have enough anodes designed into the housing and some/many of them experienced corrosion of the housing. The Bravo 1 & 2's were fine because they had 1 propeller and therefore less stronger metal.

In about 2004 Mercruiser added more anodes to the Bravo 3 to address the earlier problems. since you have a 2000 model year (IIRC), you will need to take greater precautions and pay closer attention to the outdrives.

I ran the Bravo 1 outdrive in salt for 7 years and now have run the Bravo 3 outdrives in salt water for 8 years. In both cases the boat stays/stayed in the water (mooring) from June - October. Not sure how long the 'season' is in LA, or when you plan to pull the boat for off-season maintenance.

My recommendation would be to . . .

Get the retrofit kit for the prop mounted anode, if you don't already have it.

Aluminum anodes

Fresh anodes every 3-4 months of time in the water. Keep an eye on the anodes for how much they deplete and adjust accordingly.

I actually paint the props with cold galvanizing compound to put some more weak metal right on the strongest metal.

Mercruiser has the Mercathode system, which also provides electrons to the stronger metal, saving the weaker metal. Make sure it is working correctly.

The whole outdrive will also need antifouling paint . . . props, everything. The bellows will need AF paint as well. I have found that spraying the paint can be effective in reaching the bellows and difficult areas around the transom assembly. the outdrive itself can be painted with a roller or spray.

After 4 months in the water, you can do this all over again. For us folks in the colder climates, that ends up being a season for us and we have the winter to prep for next year.

Anyway . . . I've seen more corrosion damage to outdrives kept in fresh water and neglected than salt water and maintained.

So, salt water results in a greater amount of galvanic corrosion . . . the thing is to let the anodes take the burden rather than the outdrive itself.
 
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tpenfield said:
I think the best thing is to talk to and get information from people who actually run /keep their outdrives in salt water. (like me . . . )

For the Bravo 3 drives. . .

The problem with the Bravo drives is that there is too much stainless steel (propellers, prop shafts, etc) for the amount of aluminum (casings/housings). Different metals placed in water experience electrolysis which is the transfer of electrons from the 'weak' metals to the 'stronger' metals . . . resulting in galvanic corrosion. So the weaker metals depletes one molecule at a time . . . since much of the outdrive housing and transom mounting is aluminum, they yield material to the stronger metals in the outdrive (steel/Stainless steel).

Dual prop outdrives experience this . . . regardless of brand. The critical aspect is how the drive deals with the depletion of material from the weaker metals. The solution has been and continues to be the attachment of a weaker metal to the outdrive, making the aluminum housing no longer the weakest metal.

The early Bravo 3 drives did not have enough anodes designed into the housing and some/many of them experienced corrosion of the housing. The Bravo 1 & 2's were fine because they had 1 propeller and therefore less stronger metal.

In about 2004 Mercruiser added more anodes to the Bravo 3 to address the earlier problems. since you have a 2000 model year (IIRC), you will need to take greater precautions and pay closer attention to the outdrives.

I ran the Bravo 1 outdrive in salt for 7 years and now have run the Bravo 3 outdrives in salt water for 8 years. In both cases the boat stays/stayed in the water (mooring) from June - October. Not sure how long the 'season' is in LA, or when you plan to pull the boat for off-season maintenance.

My recommendation would be to . . .

Get the retrofit kit for the prop mounted anode, if you don't already have it.

Aluminum anodes

Fresh anodes every 3-4 months of time in the water. Keep an eye on the anodes for how much they deplete and adjust accordingly.

I actually paint the props with cold galvanizing compound to put some more weak metal right on the strongest metal.

Mercruiser has the Mercathode system, which also provides electrons to the stronger metal, saving the weaker metal. Make sure it is working correctly.

The whole outdrive will also need antifouling paint . . . props, everything. The bellows will need AF paint as well. I have found that spraying the paint can be effective in reaching the bellows and difficult areas around the transom assembly. the outdrive itself can be painted with a roller or spray.

After 4 months in the water, you can do this all over again. For us folks in the colder climates, that ends up being a season for us and we have the winter to prep for next year.

Anyway . . . I've seen more corrosion damage to outdrives kept in fresh water and neglected than salt water and maintained.

So, salt water results in a greater amount of galvanic corrosion . . . the thing is to let the anodes take the burden rather than the outdrive itself.
Click to expand...


This is one of the best descriptions I've heard for Galvanic Corrosion. Thanks.

Also, I had no idea you could paint bellows with AF paint?.
 
Ted is the best at taking care of his stuff

This is a shore power addition (slat water only)
If your plugged into shore power you need to have your mercathode system checked for correct output. The output should be between 750 to 1180 Millivolts using a digital meter (Being closer to the 950 mV is best). Adding more anodes doesn't help and can hurt depending on the voltage protection level. The meter negative terminal is connected to the boats ground and the positive lead is connected to the reference electrode.

Reference electrodes are made of Copper-Copper Sulfate and Silver-Silver Chloride
The Merc electrode part number is 91-76675T 1

Edit: part has been superseded by 8M0135998
 
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