My machine gergles and then the needle starts to vivbrate back and forth without touching the pedal. It seems like it starts doing this after it is on for a while.

The walking foot lever is not touching the material . is the knee pedal adjusted right . is the manul lever on the back down.

There are two types of bobbin mechanism, rotary and oscillating, rotary goes one way and oscillating goes back and forth, if the needle is hitting the bobbin case or raceway either the needle is bent or thge machine needs retiming

Make sure the divot in the needle is facing the bobbin case.
Thread can be wound up in the rear of the bobbin case causing a delayed advance... This is often not visible when bobbin is removed.

The only thing that comes to mind is that the bobbin winder is not put back in the sewing position. I don't know how you do your machine but maybe move the bobbin winder mechanism back and forth or if it is a clutch in your handwheel make sure that it is engaged. Other than that, I would call Singer at 1-800-4singer

Before all else. Turn off machine!
(1) break screws on the hook loose.
(2) tighten one back up very skightly, one you can reach when the needle bar is at its lowest position.
(3) lower needle bar to its lowest position.
(4) loosen the screw just tightened.
(5) position the tip of the hook behind the needle hole. the tip should be as close to the needle hole as possible without actually touching the needle
(6) tighten screws
(7) slowly hand turn the machine (depress the foot pedal to disengage clutch brake on motor) several revolutions to make sure the needle doesn't hit anything on the hook.
(8) if it passes this test, try on a scrap of fabric

Needle Faces Where?  
I Need to Tighten the Tension....  
Changing a Needle  
Need Help  
Basic Questions-  
Bobbin Assembly Popped Out!  
Do You Think My Machine is Fixable?  
How to Change a Broken Needle  
Needle Bar Adjustment  
Oiling an Elna 3007  
Getting the Timing Belt Off?  
What Size Needles for My Machine?  
How to Oil my Machine?  
Where to Oil??  
Stitch Length Knob Woes  
Can't Seem to Put the Bobbin in Correctly  
Timing Belt Tension  
Adjustments  
Running Very Slow-  
Oiling Points on Singer 257  
Oiling My Singer Touch & Sew  
Singer 457  
Featherweight Case Odor  
Brother XL2010 Q's  
Does My Machine Have More Than One Belt?  
Cannot Seem To Adjust the Tension  
What to Do About a Gumming Up Needle  
How Tighten My Bobbin Tension, Please  
Is it Covered Under Warranty?  
Proper Threading Instructions?  
Just a Foot Pedal?  
Simple Threading Instructions for a 1036  
Threading a Singer 600  
Replacing a Blade on a Johnson Ruffler  
Changing the Needle  
Lubricating a Singer 1036  
Thread Balling Underneath  
Warranty Info  
Machine Covered in Hardened Oil  
Spindle Stuck?  
Do Motors Die?  
Singer 457  
Brother Sewing Machine  
Servicing My Machine-  
Belt Replacement  
Lubricating My Sewing Machine  

check out this  good luck  thanks.

Needle Faces Where?  
I Need to Tighten the Tension....  
Changing a Needle  
Need Help  
Basic Questions-  
Bobbin Assembly Popped Out!  
Do You Think My Machine is Fixable?  
How to Change a Broken Needle  
Needle Bar Adjustment  
Oiling an Elna 3007  
Getting the Timing Belt Off?  
What Size Needles for My Machine?  
How to Oil my Machine?  
Where to Oil??  
Stitch Length Knob Woes  
Can't Seem to Put the Bobbin in Correctly  
Timing Belt Tension  
Adjustments  
Running Very Slow-  
Oiling Points on Singer 257  
Oiling My Singer Touch & Sew  
Singer 457  
Featherweight Case Odor  
Brother XL2010 Q's  
Does My Machine Have More Than One Belt?  
Cannot Seem To Adjust the Tension  
What to Do About a Gumming Up Needle  
How Tighten My Bobbin Tension, Please  
Is it Covered Under Warranty?  
Proper Threading Instructions?  
Just a Foot Pedal?  
Simple Threading Instructions for a 1036  
Threading a Singer 600  
Replacing a Blade on a Johnson Ruffler  
Changing the Needle  
Lubricating a Singer 1036  
Thread Balling Underneath  
Warranty Info  
Machine Covered in Hardened Oil  
Spindle Stuck?  
Do Motors Die?  
Singer 457  
Brother Sewing Machine  
Servicing My Machine-  
Belt Replacement  
Lubricating My Sewing Machine  
check out this. good luck. thanks

When I have this problem, I turn the knob back and forth (gently) to try to get the needle to release and lift. I get this error message when the needle has shifted (either in the fabric or from using the machine alot at the needle placement shifts).
check your needle, it probably has shifted a bit.

There is no suppressor in the foot control of a 425. Only the control unit, which may need to be replaced. If the machine accelerates to full speed, it may have a problem with the "stop right" board which tells the machine whether to stop with the needle up.
You could have several problems, so go see a qualified Husqvarna repairman. You may contact Husqvarna customer service to locate the best one in your area.