I've been fighting this little Empire #90's performance for a bit now. Sometimes it would run okay but mostly not so good. I actually put it on my shelf but was pondering about it.

Finally I actually had a good idea, check how the steam pipe is setting on the cylinder. I found the pipe was malformed. So I used a small fine file to get the pipe as flat as possible against the cylinder.

Voilà problem solved! It will even run really well after turning off the power.