In article ,
Darkstar wrote:

Hi All
Just fired up a 5904 I bought last week and I am having trouble with the
variable speed. At speeds below about 1300 rpm, the speed control slowly
rotates until its going as slow as it can. Over 1300, it works great.
Anybody had this problem or know of a fix. Thanks

I think you have air in the hydraulic system. The fix is to bleed the
air out of the system. The instructions are in the manual (available
from Clausing for ~$25.00). You will need to get some hydraulic fluid.
Clausing recommends Mobil DTE24, which is available from MSC.

Joe Gwinn