Ice maker shut off arm will not stay in the up/off position

Unable to lock the shut off arm of the ice maker in the up position. I’m not sure if it is a new spring needed or something else.

The ice maker head should be taken apart to find out exactly what is wrong.

Here are the breakdown diagrams and http://www.appliancepartspros.com/partsearch/model.aspx?model_id=114087&diagram_id=254645

Gene.