: Since I've "retired" from construction, my 77 has sat a really long
: time.
: I'm looking for info re what weight oil to put into it and what else I might
: do to be sure it is in good running order BEFORE pulling the trigger....

: any suggestions?

Those are nice saws and I'm glad to see that you want to treat yours properly.

Skil has a web page with instruction books from their products.

http://www.skil.com/Help+With+Tools/Help+With+Tools+Sub+Pages/Instruction+Manuals.htm

Then click on the item in the left column for instruction books.

I followed the links for the HD77M to check out their site. After getting to the URL below, I skipped to page 10 of the .pdf document for their instructions on lubricating the HD77M, which I'm assuming is similar to your saw. (If your saw is a different model, look for the appropriate book on this list: http://www.skil.com/Help+With+Tools/Help+With+Tools+Sub+Pages/Instruction+Manuals.htm

In this case Skil recommends using their proprietary lubricant, and gives three part numbers which reflect the varying sizes of the packaging.
These would be skil parts 80111 ( 8 ounce tube), 80112 (pint) and 80113 ( 1/2 gallon can). The manual specifies a procedure for cleaning out old and dirty oil with a kerosene flush before refilling with their lubricant.

http://www.skil.com/NR/rdonlyres/e6hkx325cvx54fr5yytjlrwsc6dc5dbjc66yjtp7tddhah5u65ezgegfshceiio5seovv35ayvcxp7jizlo3zgcohag/2610905550+1-03+HD77%2c+77M.pdf

hope this helps

PGJ