1963 Johnson 3 hp sediment issue

[Dave1027]

I'm refurbishing an old Johnson 3 hp. It's a 1963 model number JW18R but it's basically the same as all 3 hp Johnsons and Evinrudes made from 1951 to 1967.

I pulled the head off, removed the old head gasket and found the water jacket full of sediment. I'm thinking the previous owner hit bottom and sucked up sand. My question, how do I remove the sediment? Can I remove lower unit and somehow back flush it?

Thanks,
Dave

 

[Crosbyman]

first protect the cyl by stuffing them with rags

you can physically start by scrapping the deposits out with a stiff wire , or narrow blade

then use /swab hot vinigar & let to stand a few minutes

it can react with mineral deposits to soften things up .

you can then use a narrow brass wire brush to go around the cyl walls .

as to the innards ..well hopefully not being exposed to to much heat the minerals did not accumulate so much

that is what I do