I have an old medium sized 1/2 HP electric [motor]. On the bottom, on both ends, there is a small (couple millimeter) hole blocked with red plastic plugs. They are on the same side as the mounting rig, on what I would call the bottom of the [motor] (the info plate is right side up when the plugs face the floor).
Looking online I see some engines have drainage holes that come stoppered with plastic plugs (you remove all of the ones that end up facing the floor). But I have been told that these [motors] sometimes come with similar stoppered holes for oiling. How would one go about telling the difference?