A great time with great engines.
What's the back story for the huge boiler engine?
Hi Chris, sorry it took so long to answer this.
We believe it may be the first #20 sized Big Power Plant Engine.
The boiler is 6" in diameter by 8" long, has a 600 watt heater. It is the only one we've seen that is shorter and not on a Jensen #50.
This boiler would be the prototype for that used on the earliest Jensen #50's of which 3 are known to have a 6" diameter boiler that is 9.75" long.
The engine part is most likely the prototype of that which was used on Jack's slide valve Jensen which is likely the one used on the earliest Jensen advertising and brochures.
Gil