2000 Merc 200 EFI melted rectifier

[Kzaker]

I have the above motor (SN: OT153942). The charging has never worked since I owned the motor (last year). I haven’t needed to additional charge but want to get it fixed. The battery, when charged is just over 12v and I get no additional voltage when running at any RPM. I found one of the rectifiers is melted a bit and was going to swap it out but figured I’d ask the collective of experts here if there is anything additional I should do OR, swap them out and see if the problem is fixed. I’m also buying a lead acid battery to replace the AGM that the previous owner had installed (which may have caused the problem to begin with). I thought I had read that Mercury had new rectifiers to replace the old design and they solved many of these problems- anyone know anything about this? I’ve also read that both should be changed at the same time. I will continue to research this for myself but it never hurts to ask someone (you guys) who have been here before.

thanks for taking the time to read this, I appreciate any input/advice in advance!
Regards,
Karl

[CatFan]

Replace both of the rectifiers with OEM current parts. I doubt the battery had any part in the problem unless it was bad. Be sure to charge the battery between trips to minimize the load on your charging system.

[Kzaker]

Thanks. I have read that these motor without alternators are not designed to handle the stress of optima AGM’s and everything I read tells me the same thing. I hate to buy another battery since that one is fairly new. Hopefully I’ll get some more recommendations from people with more experience than myself. Regulators: $250 a piece is already a ding in the wallet, don’t want to spend more on a battery:)

[Rip Bass]

I remember reading the same about those older Mercs. Go to the Mercury pages and look at the sticky notes up top,you may find more info about this.