Hello. Understand from the post that the engine comes from the furnace screw feeder? Choosing a capacitor for a 1-phase motor with an auxiliary winding is not easy because it has a different winding than the main winding - you cannot be guided by the power of the main winding when selecting a capacitor working with the auxiliary winding. Actually, you need to know the motor data, such as power, RPM, the nature of the load in which it works and a number of others, including the recommended capacitor capacity - and this is not what you are looking for. Usually, if the value on the capacitor is unreadable, it should be on the rating plate, but not all manufacturers put the capacitance on it.
For you, I have presented several values of the motor power and capacitor capacity in the auxiliary winding, selected for most cases, but these values may differ, and quite a lot, even so please treat them as more indicative Pn [W] 90, 120, 180, 250, 370, 550 , 750, 1100 and their capacitors C [uF] 4, 5, 6, 8, 12, 16, 20, 30
