Zinc Installation in Heat Exchanger

[Bad Dad]

Hey Everybody. I have my heat exchangers pulled for cleaning and I want to add zincs. Can anyone tell me if they go in the input or output end or does it matter? These are on Merc 454s. Thanks, Dave

[Bruce]

Either end as long as it's in the saltwater side. Usually they have a drain plug you can replace with a pencil.

Do the Mercruisers have the Mercathode system? If so you don't need to add pencils.

[Bad Dad]

That makes sense Bruce, and explains why I don't have them Thanks very much for the reply.