Yamaha Internal Anodes

[ChrisF]

Does anyone have a decent picture that illustrates the location of the "cylinder head annodes" on a Yamaha 150 HPDI (or similar)? I'm looking at the service manual and I cant quite get it from the diagrams in the book.

[ChrisF]

After spending some more time gazing at the service manual, I now understand why my question isn't so simple. The HPDI maintenance schedule says these internal anodes should be inspected and replaced as necessary every year or 200 hrs, but I can’t imagine anyone actually doing this. Seven of the eight anodes are buried under the cylinder head cover. You have to remove the cover, the 28 bolts that hold it to the block, and a non-reusable head gasket in order to get at them (something I’d just assume leave to the pros…). The eighth anode appears to be a bit more accessible, located on top of motor on the starboard side. I plan to look for it when I do my annual maintenance stuff next month. I'll post a picture if I find it.

If I do find it, my plan is to check the one I can get to and, if it needs to be replaced, pay someone more qualified than me to do the other seven. My assumption being that the internal anodes wear at an roughly equal rate, so if the one I can get to looks good, the other seven are probably good as well.

[dans]

Don't worry about them unless you are removing the heads for a diff. reason. The water flows by them too fast for them to do any good.