Does an old automatic oiling system tells you when it's caput ? will tell you when you have already a screwed engine due to oiling system failing. Are variable systems at idle, fast idle, up to certain amout of throtttle, passing that settting all works 50:1 ratio mixing specially if it's a oldie engine. For your peace of mind and credit card, install a new one if with fear will fail at any future time.
Happy Boating