trouble shooting a single acting steam engine

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


New Member
Mar 27, 2021
Reaction score
United States
I recently bought a PM research #3 steam engine machined kit. I wanted another working engine in front of me to gain experience before I started making my own models.

It is a single acting engine with a piston valve modelled after stationary engines used for milling. Steam Engine #3 - PM Research

The piston valve did not fit properly to begin with and after some forcing finally went all the way in like it was suppose to and now runs smooth by hand. The only thing I could figure was there was a imperfection when the casting was machined. Hopefully poor tolerances or leakages is not the cause of my current problems.

Currently if I adjust the eccentric just right it will run very well with a lot of speed for a few seconds and then peter out stuck in the return position. I have tried every position possible while adjusting the eccentric and so far no fix. I am wondering if I need to make a heavier fly wheel for this model so there is momentum to carry it through and it wont get stuck. Most steam engine videos deal with double acting slide valve engines with a steam chest so they are not a lot of help. Advice would be greatly appreciated.
Keith Appleton, one of the top youtube steam engine experts, shows exactly how to tune the pm#3. Fyi, the #3 is double acting.

Latest posts