Yanmar 2qm15 zinc anodes

[Jack Long]

I am attempting to inspect/replace the zinc anodes in my Yanmar. I am using the Yanmar Service Manual for the motor that some god-send linked to me in another thread. Not the owner's manual- but the service manual. Lots of good diagrams and whatever else.

Anyway, I started to remove one and began to second guess my interpretation of the diagram from the manual. The thing was torqued on like an angry titan installed it last. The entire assembly came loose before the nut broke. Had I been standing on the dock instead of the cabin sole I think I could have rolled the boat over. Then I noticed on the grease and crud a red sticker. It read "zinc inside" so I felt pretty sure this was, in fact, the right thing.

I scraped it off, saturated it with WD40, resaturated, etc... It still doesn't want to budge. The one in the back seems to be on with similar levels of never-****ing-let-go.

Any suggestions? I might be able to get a breaker-bar onto the front one- although this is the one that the assembly wants to spin... But I don't think I can do anything to increase the torque on the back one...

[jlogan]

For metal objects corroded together, the time-honored system is penetrant - something better than wd-40, like PB Blaster or such, heat, and tapping with a small hammer. the repeated cycles of penetrant, tapping, and heating and cooling expansion usually will break things loose. Patience is a virtue..

[Liberty28]

I got exactly the same thing on a 26 year old Westerbeke w21. It's been in freshwater it's entire lifetime, but that zinc is "welded" into the heat exchanger. At least I've got room to work on it, but I know that if I get too aggressive, that darn bolt head is going to torque right off the bolt.

Gawd I love working on boats. So much to do with so little space!!!!!!!!!!!!!!!!!!

Good luck to both of us!!