Necchi 3102 Mechanical Sewing Machine "dryer gets really hot touch" Questions

...really don't want to chip a gear tooth. Finding a replacement might be next to impossible. Hair dryer or a heat gun on the lower setting will help to soften old oil and grease also. Heat guns can ...

gets gummed up from lack of use/dirt/lint/grotty oil and may just need a good clean inside. Other possibility is the spring on the needle bar has broken. To test this, set machine stitch width to zero