Water jackets are diverent from oil lines (as the names says)
If you want to get rid of all the gunk that accumulated over the years in the water jacket get 2 gallons of phosphor acid (same thing like in Pepsi and Coke). Mix it with 2 gallons of water. Block of the opening in the front of the block and head (waterpump and all others). Fill it at the little holes where the head and the block mates. Let it sit for a day or 2.
That not only removes all the rust it leaves a phosphate layer that protects it from future rust.
Flush everything with a garden hose for 30 minutes.
Be carefull, wear rubber gloves and googles. That acid wil not eat your hand to the bare bones but try not to get to much contact. Do it outside, because of the fumes.
I did this twice and it works just great.
It will not harm your new machine work but will leave a ugly looking brown layer on it that can be removed with soap water and some polish.
Frank
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