Hi Greg, I also like to run them real slow. This engine is still not timed properly to run super slow.
Could you have mistaken slow motion for super slow?
It will run real fast!
This one seems set up to run fast.
Soon I will make a short video of it running at 800 RPM plus.
Here is a Stuart 5A that is more properly set up and doesn't have the extra load and friction of all 3 pumps (it has one pump).