What's this on my lower unit?

[duped]

I'm sure these threads never get old...Working on my 85 Sea Ray with twin 5.7s Alpha Ones. One drive is original, the other is a 1988 going by the serial. The 1988 lower unit has this odd "thing" bolted to the end of it, it has two bolts, one on each side that seem to hold it on and the propshaft passes through it. Anyways, my other lower unit from 85 does not have this, I see the threaded holes for bolting it on, but it's not there. If I recall my 1986 Alpha doesn't have it either. What is it and what does it do? Can I clean it?

 

[Dave-R]

It might be a fishing line cutter. Some put these on to keep the props shaft seal from being cut by fishing line. Not sure though, I do think you need to take the props off more often, and grease the splines. Dave-R

 

[Bt Doctur]

Called a zinc, helps prevent electrolsys

 

[enginesilo]

Like BT said, it is a zinc to attract growth as a sacrificial metal. If you buy a set of anodes it should come with that one. When I first got an I/O I had no clue there was a zinc back there either.

 

[Fun Times]

Since you seem to have bearing carrier part number 818763A10 -- (gear housing casting #73020C1), Mercruiser part number 806105Q1 which is an aluminum bearing carrier anode should fit on your bearing carrier. It's time for a new one.
http://www.iboats.com/Search/dm/?key...ch_submit.y=25

Quick Notes:
Magnesium Is Good For Fresh Water Use!
Aluminum Anodes Are Good For Salt And Brackish Water!
Zincs Are Good For Salt Water Use!

818763A10 - BEARING CARRIER ASSEMBLYBearing Carrier Casting # 73020C 1 Fits MR, Alpha One, Alpha One Gen II and Vazer.