David
The motor, assuming it is a speed 300 motor, has a max no load speed of 29,000 rpm. If you set the RPM off higher than this you may well find the engine will hang onto the starter and get hot.
Yes I use the Hausl magnetically coupled pumps for my Sprite engines as well as the 44. It is interesting to see inside it and it truly does not have a direct drive to the gear. However all brushed pumps have problems. I have had problems with one of my magnetic Hausl pumps sticking until I give it a quick burst of electrically to free it. All the Flightworks small pumps I used had problems with as they kept sticking. The best by far was the larger Xicoy brushed pump, but I know they are carefully tested before leaving the factory, however they are in short supply.
With Flightworks pumps you will probably find that the auto + settings do not work and you have to give it a fixed value.
John