Imagine you are a lighthouse keeper on the graveyard shift on a foggy night. All you hear are the diesel engines running, the foghorn blowing at intervals. As you stare out into the gloomy mist you hear this sound. It is a boat, but what kind of boat? What kind of motor?
Many old-timers will recognize it as the sound of a classic make and break Easthope 2-stroke marine gasoline engine on idle. It probably belonged to a fisherman waiting out the fog so he could see where he was going. It was a sound that carried through the fog just like the foghorn.
To hear it again brings back many memories. If you wish to see the fishboat that housed this engine take a look at this Youtube page.