Warrend,


Allan is right about the break-in.
This engine has strong parts that need more than a few minutes of break-in.

It will take several running hours until it begins to behave perfectly.

With the low-end mixture setting too rich, this engine has a strong tendency to load-up and upon throttle-up, to back-fire and to throw the prop!

With the Perry pump, this tendency is increased, so you must both lower the pump pressure somewhat and close the low-speed needle, until it runs well and transitions reliably from low-throttle.
The instructions that came with your Perry pump explain the extent, to which you should adjust these control.