I have a Consew 2230 the timing keeps on loosening and bracking my needkes when I start speendig it's shifting a bit because it't loose.I have tried to toghten the scres ghey are tight

Take it to a service centre. Setting sewing machine timing is a job for a professional. It has to be exact to within half a millimeter and also the correct torque on the screws so they don't slip, but not strip the screw threads.

https://www.google.com/search?q=Consew+2230+timing

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I am not sure about this particular machine but in most machines there will be a nob on the front loose low numbers like 0 1 -2 work well on number 3. If the nob is not on the front check and see if it is on the side.

Hi,
That's a great old machine, this link will help you keep it running.
Bob http://www.consew.com/Files/112347/PartsBooks/118.pdf

THE SPRING THAT TIGHTENS AGAINST THE THREAD IS BENT OUTWARDS. IT MUST BE BENT INWARDS BY KEEPING THE TIP HELD UP WHILE YOU PUSH DOWN ON THE SPRING WITH A SMALL SCREWDRIVER. THIS WILL BEND THE METAL INWARDS. NOW, WHEN YOU TIGHTEN THE SPRING AGAINST THE THREAD IT SHOULD TIGHTEN AND LOOSEN AS YOU ADJUST IT. TO ADJUST YOU JUST NEED TO HANG THE BOBBIN FROM YOUR FINGER AND BOB IT UP AND DOWN. WHEN YOU ADJUST IT PROPERLY THE BOB WILL CAUSE THE THREAD TO EXTEND ONE INCH. THIS HAS NOTHING TO DO WITH TIMING SO DON'T BE CONCERNED ABOUT THIS.

Your belt may be to tight you can loosen the belt at the wheel under the table. Loosen the screws and shift so the belt loosens.

I’m happy to help further over the phone at https://www.6ya.com/expert/marion_ba76620b6989fe02

The bobbin should have a thin metal peice that the thread goes under to create tension, the screw closes to end the thread comes out of is the one to adjust. If they were sewing with a light thread on the machine the tension on the bobbin is probably set pretty tight loosen it a little at a time, turning the screw counter clockwise. You might need to check your top tension also if it is showing a knot on the bottom. The bottom is to tight or the top is to loose.

buy smaller motor pulley this will reduce machine speed

take it to a serviceman.

do you have the user manual?