Abstract: A compressor capacity control and lubrication system including a nonmodulating capacity regulator for an oil flooded gas compressor such as a rotary screw compressor. The system includes an on-off intake regulator. The lubrication system insures sufficient supply of cooling and sealing lubrication when the machine is operating at loaded conditions and a limited quantity of cooling lubrication when the machine is operating at unloaded conditions. This is accomplished by the use of a pair of gas-liquid reservoirs. One of the reservoirs is vented to atmosphere during unloaded operation of the compressor. Lubricant is supplied from both reservoirs to the compressor when the machine is operating at loaded conditions, but only one of the reservoirs when operating at unloaded conditions.