I found my nipple.
I had a brainstorm - having one hose loose at one end, I would just fill the fresh water system, put my thumb over the loose end and look for where the water came out. Voila, it came gushing out from under the water pump. I learned a lot today. I just hope I've fixed my overheating
problem. Otherwise, I'll be back for more advice.
The schematic diagram for the Universal M-18 engine just shows fresh water re-entering the block. Does it make sense that the cooler water re-enters the block near where the heated water comes out? I can't imagine it's a double action pump, sending warm out and cooled in (like a double action head
pump sends fresh water into the bowl and soiled water out). Does that make sense? Cooled water could enter anywhere on the block and it's just a coincidence that on mine it's located nearby?
Thanks, Dave, for the suggestion about google/images That's a great site!