Reassemble diagram if a thread tension button on Morse 4300

The Morse 4300 and 4400 use the same small 15W screw in light bulb as many other sewing machines. This is one vendor: Bulb 15 Watt Small screw in base A1 Sewing Machine Specialists

The Morse 4300 and 4400 use the same small 15W screw in light bulb as many other sewing machines. This is one vendor: https://a1sewingmachine.com/LB716sm~Bulb%2C+15+Watt+Small+screw+in+base.htm . Another source is https://www.sewingpartsonline.com/light-bulb-white-7scw.aspx .

I hope this helps. However, if you have a bulb in the sewing machine, take it out and confirm that it is the screw in type. (If there is no bulb, look at the socket for some turns for threading in a bulb.) If the bulb or socket doesn't have threads, then look for a 15W push and twist bulb at sewing machine parts suppliers.

Cindy Wells

Oops! All sewing machine diagrams/manuals are available, online. Oddly. From the late 1800's, on.

Perhaps this will help:

Morse 300 Sewing Machine Threading Diagram

Morse Pushbutton ZigZag Sewing Machine Threading Diagram

Morse Sewing Machine Instruction Manuals and Repair Manuals

...

Perhaps these will help:

Morse 6400 Sewing Machine Threading Diagram

Morse Sewing Machine Instruction Manuals and Repair Manuals

http://www.sewusa.com/Sewing_Machine_Manuals/Morse_Sewing_Machines.htm

manual for a vintage Morse 550 zig-zag Kathleen, Check the attached links,manuals and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
Morse 550 zig zag manual Google Search
Morse 4300 Zig Zag Sewing Machine Instruction Manual Fotomatic III
Morse Pushbutton ZigZag Sewing Machine Threading Diagram
http://www.sewusa.com/Sewing_Machine_Manuals/Morse_Sewing_Machines.htm

I cant find any free manuals sorry. But there is one for $4.99

Morse 4300 Zig Zag Sewing Machine Instruction Manual Fotomatic III

change the needle--one that is correct for the fabric being sewed
check the needle plate and see if there are any burrs--if there
are gently use a small file to take off the burr
check with sewvacdoctor.com,,,or ,,a1sewingmachines.com
or sewusa.com about a manual,,, you'll have to call them or
email them about the manual..
the tenison dial may need to be replaced.

if all the dial are set correctly for the zig zag, and the machine
still won't do the zig zag stitch then it's possible that there is a
gear or cam inside the machine that is worn or damaged.
a sewing machine shop can tell you for sure.

Check out this web page for instructions:

http://www.sewusa.com/Threading_Diagrams/Threading_Pages/Morse_Sewing_Machine_Threading/Morse_4300_threading_Diagram.htm