This is a Westerbeke 12C-Two marine diesel engine and Hurth transmission with low hours. Originally installed around 2001 in a Landing School 26 (see SailboatData). The boat owner has replaced it with a whisper quiet electric drive system because the owner usually sailed on and off his mooring and seldom motored anywhere. Makes sense and kept the hours very low. This motor did not have an hour meter on it (why? I don't know), but an identical motor from an older LS-26 (used and converted the same way) had 280 hours on its hour-meter.
The Westerbeke 12C-Two is a great motor and is still in production as the 12D-Two. It is lightweight and low-revving Mitsubishi base motor with lots of torque. You can find full specs at https://www.westerbeke.com/Category/12CTwo/5399ADA2DAF73A26740BF64D#techdocs
Its only obvious flaw is that the paint on the transmission is flaking off. I was told that was due to the cover being left ajar in the yard over a winter exposing only the back half of the motor. Thus, it has some paint blemishes but has otherwise been well cared for over the years.
I have a video of the engine running in my driveway. Please contact me for more information about this.
The motor is in Rumford, RI and can be picked up there. Alternatively, crating and shipping can be arranged at buyer's expense. (Typically about $300)