Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

  I have a pmr #1 that runs but feels stiff - not the rod or crankshaft,
they are good.  It almost feels like there are 'O' rings....on the piston?
Could this be so?  And if so, how many should there be?  The builder
put three rings on the feed pump ram, more than the instructions,
but it worked with some fussing.

The problem can be o'rings, but it can also come from some misalignment of internal parts of the engine.  Did the builder make a good "break-in" ?  PMR provide teflon rings instead of o'rings, but the builder could choose for any reasons to put o'rings,  that work too.  For myself, I think your best way is to look inside for some wear and alignment of the piston and rod.
And I agree about the copyright, but can give you the dimensions you need...