Nice catch, especially the instruction sheet.
The unplated copper boilers look really nice
and I'm a sucker for these Empire No.92 Play Boy
engines. One has no sightglass/fittings and the
sight glass holes are bored over-sized - but the
engine does run. I've had 4 and the heaters were
cooked on two. I have one whose heater is good
and runs well and another with a replacement
heater that runs well IF I liberally apply steam
oil to the cylinder and piston. Keep in mind,
the boiler is rather small and you will not get
a long run-time. To maximize, use a voltage
reducer like a variac or an incandescent bulb
dimmer. I've added a video.
As to your problem. Is the water coming out
of the back of the cylinder, or is it coming from
the cylinder/valve-plate area? The latter might
just need tightening. The former, well, the engine
I use the steam oil on has a different cylinder and
the piston is removable, allowing me to do a good
oiling. Yours looks like a different cylinder with
a non-removable piston. Try steam oil on the rod
and cylinder end and maybe enough will get in to help.
Don't give up hope. You will beat it into submission!
The working heater is a good start.
God Luck,
Wayne