I was under the impression that Honda had free factory service manuals available, but this is all I could find.
https://publications.powerequipment.honda.com/details/61VE2640E5
Here is a free PDF for the engine alone.
http://www.honda-engines-eu.com/shop-manuals?e=0_66&p=all&d=all&l=all&t=all
Thank you Sparkland.
I went ahead and purchased the HRB215 Lawn Mower Service manual from the American Honda Power Equipment website you linked to... and the Parts lists for both the K3 (what I have) and K4 (what superceded my model), as well as the 7 ring binder to keep the three publications neat and tidy. I feel like a fool for spending so much ($92) when it seems like after 20 years, this information should be available online somewhere... but I have found that paper manuals are a lot easier for me to browse and refer back to than manuals that require a computer to be on and running in order to see them.
Plus I've lost a few harddrives, as well as entire computers, to both failure and theft. But no one seems to want to steal books, and books don't have head crashes... so maybe that was my way of justifying spending so much to avoid messing up the lawnmower in ignorance. Not knowing what I don't know is a conundrum.
I did go to the European Honda website and grabbed the pdf file for the GXV140 engine, which saved $39.00. It is hard to read, as the pdf interleaves several languages in between the pages, even though the download section offers the manual seemingly in five separate languages. The truth appears to be that all five links point to the same mulit language manual, which disrupts the continuity of trying to scroll up and down with Adobe's latest version of their pdf reader, wondering if a paragraph in English was missed along the way while wading through the other languages interspersed in the pages. I might end up ordering the manual in print after all.
I did check eBay for manuals. eBay used to present a great value for such things 20 years ago, when dealerships closed or chucked out old service manuals to be replaced by updated ones. But nowadays, ebay has devolved to people selling crude photocopies of service manuals... for nearly the same price as professionally printed and bound versions from the manufacturer, so why give the hucksters on ebay nearly the same amount of money for an inferior reproduction of copyrighted material? (Again, more internal self justification for putting a near $100 hole in my savings to save from ignorance... and most of you probably aren't buying it.)
Thanks again for the links. I'll let you guys know when the manuals arrive.