Look on the forum home page, toward bottom of page, under red bar that says "Library", then look for "Hi-Lo Owners Manual". You'll find a collection of them.
I own a 1990 25ft. Classic HiLo. Another forum member was kind enough to scan my lengthy owners manual into the library. Hope this helps you. Welcome to the forum.
If you find a manual listed for anything close to your model year you should be good. The manuals a not model specific and change little from year to year. The are no water line diagrams to be had.