So yesterday I went to apply TSB 2276R1 to my 1989 Johnson 70, as detailed here: http://forums.iboats.com/engine-frequently-asked-questions-faq/johnson-evinrude-adding-tell-tale-222677.html. I have a very occasional overheat problem, so wanted to bring the motor up to date with all the TSBs.
I got my 1/8 NPT tap and drill and was ready to go. It didn't look like a tough job, but drilling into an engine block is something I'm never going to be comfortable doing. So I scoped out the location for the telltale nipple. Hmm, a bolt right near there. I removed it - not a bolt, but a pipe plug with a hex head, never seen that before. Turns out the replacement powerhead put on by the previous owner must have been a later block, with the hole already drilled, so all I had to do was swap the telltale nipple and the pipe plug. And the money spent on the tap wasn't a waste, as I needed to chase the threads to reinstall the nipple.
And then I slapped on the muffs and started 'er up - no leaks. I'm going to play the lottery this week.