Hi Guys:
Weve rebuilt many of both
Butler and WM units.
Running @ high RPM does not hurt as much as starting high, or with the pump on. Also a dirty blower puts too heavy a load on them, so keep it flushed. A
Butler shaft is 7/8" in dia. a White Magic is larger than that, so it won't fit.
We have found sources that make a clutch with a much stronger magnet for the
Butler, and tried them. The problem is the pulley also is much larger, so it slows down the RPM ratio. In fact I can sell you one of these, becuse I am unhappy with it,
But best bet is to sitck with original
Butlers. They are pretty tough, and normally last 3-7k hrs provided they are treated as per above. When not treated right, the magnet starts to slip and that creates heat, and that burns up the magnet, and bearings.
Thx,
Dale