Hi Marty,
Thanks for the info. I've located it and it does look like a drain screw. May be difficult to get at. But what worries me is the open drain valve on the starboard side (that is not draining yet). I'm somewhat sorry I looked. Ignorance was bliss. It may have been like this for 20 years.
Harvey Rosenberg C-27TR #6023 1985, M-18, Stony Point NY
hange-M-18 Engine
I thought that the coolant drain on my M-18 was on the port side of the reservoir , with a square nut on it , in the lower right corner. Check to see if that is really it. Just a suggestion.Marty Conceicao C#6443- Windswept.

