Re: Older 75? HP Johnson around 1975 with no serial number and no peehole??
Some older motors have no tell tale. Not very important anyway. Hole in front of LU is probably a speed pitot. Tell tale are always thru the lower pan of the powerhead housing.
Model number should be stamped into a welch plug on upper aft part of powerhead. Year can be determined from that.
The cooling water indicator is the finger size hole in the backside of the midsection. Water droplets should blow out there any time it is running. It will blow a heavier spray when the thermostat is open. It is never a "water hose" stream. The thermostat normally cycles open and closed while running, so don't be concerned about that.
Johnson motors of the era have the serial number in two places, on a metal plate usually on the stern brackets, and a round quarter-size disc on the powerhead. They don't both just happen to fall off, so if they are both missing it probably is stolen. Experienced thieves know about the two locations. Amatures sometimes don't know about the round disc.
