I just bought a second hand elna SU and the coupling wheel will not turn. ( so I cant disengage the flywheel to load a bobbin. Any suggestions?

Looks like it is an older mechanical machine, so it may be seized due to old oil that has dried.


Wheel on right side that controls the needle up and down is very tight...

Possibly a gear or something is broken too.

do you mean that you can't unlock the inner wheel on the flywheel to disengage the clutch? Grasp the outer flywheel and using a plastic mat for removing jar lids, get a good grip on the inner clutch wheel, then turn it towards you.

either a jam up in the bobbin which is preventing the needle bar from coming up, internally siezed up, or the friction belt internally to the flywheel has broken/worn out.

There are a couple of different SU models, the Star Series and the Air Electronics both had an SU (supermatic) model so I'll be general in my description. Firstly remove the needle cover plate and check around the bobbin race for jam ups. Or if the machine has been packed away for a long time unused, then we could assume this is a sieze up. FIRST REMOVE THE POWER PLUG FROM THE MACHINE FOR SAFETY. You'll need to remove the top machine cover and delve into the insides with a bit of patience, good quality sewing machine oil (tri-flow is perfect if you can obtain some, bike shops have it or I got mine from Ebay) and Qtips or something similar.

There should be a couple of screws holding the top cover onto the machine so remove these and then lift and tilt the cover to the back around the lifting handle and making sure you clear the bobbin winder mechanism on the right. Really good idea to take photos with your mobile as you go so you can remember where things went. Now apply triflow to the metal moving parts you can access, in particular the top of the Elnagraph shaft which should have a red mark for oiling point, and the needle bar swing bearing. Keep oil away from the belt/s on the right side of the machine where the flywheel is driven by the motor.

You'll need to carefully clean, oil and gently move the flywheel back and forwards until things free up.

if the machine is new & it's already making noises, the I'd suggest taking the machine back & getting another

when a hand wheel won't turn then the machine needs to be serviced

is clutch disengaged? inner wheel in flywheel, hold flywheel and turn inner knob towards you to loosen. put bobbin on spindle and move to right to wind. if youve done this already and no joy then bobbin winder tyre may have perished. try www.sewingpartsonline.com to buy new one

I can direct you to a service manual for your machine but it may be something that you need a trained Elna service technician to deal with.

Link is http://www.arizonaexpressionz.com/elna_service/air_elec_carina_elec_SM.pdf

I am more familiar with the SU air electronic where you just hold the outside of the flywheel and turn the inside knob to disengage and rengage the clutch - didn't realise the Carina had a button flywheel release until I looked in the service manual.

Anyway, you could try dismantling the flywheel following the exploded diagram in the service manual if you are technically minded.

Or just take it to a reputable serviceman, I'm a big fan to supporting these guys as their knowledge is invaluable.

On the Carina SU there is a button on the flywheel to disengage when winding a bobbin. Be sure this button is pushed in.

Wind the Bobbin
For the usual jobs, it is the best to use a medium sized thread.
2. Disengage the flywheel by unscrewing the coupling knob as far as it will go.

3. Place the bobbin on the bobbin winder, and push the bobbin winder to the right.

4. Pull out one of the spool pins and place the spool of thread on it.

5. Pass the thread through the bobbin winder tension discs, as indicated.

6. Wind the end of the thread around the bobbin by hand, in the direction indicated.

7. Wind the bobbin, at a medium speed by pressing lightly with a finger on the spool so as to stretch the thread better and thus fill the bobbin to a maximum. The full bobbin stops automatically.

8. Re-engage the flywheel by tightening the coupling knob.

9. Cut the thread and remove the bobbin from the bobbin winder by pushing the latter to the left.