RE: OEM Manual. I see a lot of people balk at the price of them, but it's the best money you'll spend if you are going to work on your engine. The same money will get you maybe an hour of time at a shop. You may get lucky and find one on e-bay, but make sure it is the OMC manual. In my opinion the Seloc and Clymer books are best used for lining a bird cage.
I got the OEM service and parts manual for around $40 for both on eBay for my motor. It's paid for itself a dozen times or more I searched by model number and year and found several of them.
Ebay - as others said - is a good place to look, and I've actually bought a couple of repair and owner's manuals there. However a good ebay price, while a significant discount from a $70 OEM manual, won't probably save you more than $25... and as you know, you can spend a lot of time waiting and looking. Sometimes it's worth some bucks just to get it done. If so, just go to the kencook.com website and just buy one.
There is an ebay seller that is worth giving an email or phone call to because he is very good and has a lot of manuals that aren't listed on ebay (I recently bought an OEM shop and owner's manual from him and he was very helpful). Search for searayman13. have to say he's a good one.
I searched by model number and year and found several of them.