Quote:
|
Originally Posted by Mee-n-Mac
I agree with your post but want to mention this issue for anyone looking to buy a used boat from the late '90's with a Bravo III sterndrive. The were enough reports of corrosion that BoatUS got involved and tried to help out. Our B3 was made after the years affected (supposedly), and I've not seen abnormal corrosion, but still I'm a bit leary of recommending a Merc B3 (especially given MerCruiser's response to the whole issue). Given a choice I'd go with a VP Duo-prop but that wouldn't be the deciding factor in a new boat purchase for use on Winni. |
I have one of the "Bad" Bravo 3 drives. The biggest mistakes with these drives that lead to corrosion (in Winnipesaukee anyway) are not knowing to leave the battery switch on and not changing to proper freshwater sacrifical anodes. The big stainless props on the Bravo 3 offer a huge cathode that is more noble than any other part of the drive. If you combine this with an aluminum drive housing and the aluminum anodes they all seem to come equipped with, the drive housing is going to corrode about as quickly as the anodes. Switch to magnesium anodes and the drive corrosion stops.
In addition to the protection offered by the sacrificial anodes, Mercruiser also installs an active corrosion reduction system called "mercathode". It is only active when it's powered so leaving the battery switch in the off position while the boat is in the water keeps this device from protecting the drive.
If you intend to have a Bravo 3 in Winnipesaukee, plan to leave the battery on and get the proper anodes. Mine has been corrosion free this way. I also take the time to make sure the drive paint is in good shape every year.
If you have shore power (not likely on a 220 Sundeck), it's a very good idea to install a galvanic isolator to stop low the voltage DC from riding on the AC line. That DC can overcome both the mecathode and the anodes and do some serious damage.