Re: 1989 OMC 200 Cobra 302 5.0
There's a lot of guys on this forum that won't touch either a Seloc or a Clymer manual. I have not had experience with them, but I am told that they are incomplete, ambiguous, and have confusing photos and diagrams.
I picked up an OEM OMC service manual on eBay. It was the best $54.90 I have ever spent on my boat. I went from not knowing anything about boats to replacing my upper unit and u-joint boot on my own, thanks to that book.
If you can find the OEM manual, I would recommend that you buy it.
Good luck.