KitchenAid stand mixer KSM150 was run without locking down the motor housing. Now the motor head "wobbles" when the mixer is operating. I've tried adjusting the screw located under the head but it continues to wobble. Could I have bent or broken something?

SOURCE: head of mixer droops

I just fixed mine this moring!!
Solution:
1- Lift head. In the lifted position you will see the head of an adjusting screw. Turn it to the left say a half turn.
2- Lower head and see if it is still too low. If so, do it again.

I had to turn mine like two plus full turns.
I beleive it goes into a nylon insert so that the threads are cut as the screw is put in the first time. If the screw is too loose, it may be possible that over time the head could slowly drop because of vibration and the screw slowly moving inward again. If that happens, a new nylon insert may be needed (but that is a different story).

There is another screw that may be loose of the head moves too much right and left. I also had that issue. This screw will be seen if you lay the machine on its side and look up the shaft (pedestal) of the base (large empty area the head attaches to). You will see a small screw head (first item up the open part). That set screw holds the unit in position on the hinge pin to stop movement from right and left.
You will find a full service manual in pdf at:
http://www.mendingshed.com/kitaidparts.html

Hope this helps.
Ken

SOURCE: Kitchenaid Mixer head wobbles bad

The solution provided by luannej is useful only if your mixing attachment is striking the surface of the bowl. By adjusting the screw located at the junction of the head and base, you are actually controlling how far the head is allowed to tilt forward and, thus, the height of the attachment above the bottom of the bowl. Although the attachment striking the bottom of the bowl will lead to wobble (and noise!), it isn't usually the root cause of the wobble. In fact, the wobble may be causing the bowl strikes and adjusting the head height only hides the problem.

The head of the mixer is secured to the base by a large steel pin. Any play between the head and base comes from this hinge and its resulting tolerances. To "tighten" the sloppy tolerances causing your wobble, follow these steps: 1) Lock the mixer's head down and turn the entire mixer upside down. 2) Looking deep into the hollow base, find the small slotted set screw. This screw actually presses against the pin and takes up the slop between the head and pin. Note that this screw is not the large slotted screw I mentioned earlier visible when you tilt the head back. 3)Tighten the small set screw as much as you can. Your wobble should be greatly reduced or eliminated now. 4) Lastly, you may want to readjust the large screw controlling the head's tilt to optimize the distance between attachment and bowl. Hope this helps.

SOURCE: My wife's kitchenaid classic 250 watt mixer wobbles on the base

It sounds like your mixer likes to take a beating, ive never dropped one and for good reason, they weigh quite a bit. first check to see if all the rubber legs on the bottom are still there. if they are the only possible solution to fix it after being bent or warped is to either re-shape the part using a tool strong enough to do the job, or to replace the parts needed. the hinge pin part number is 16910. is the base is bent the part number is 240151-1. If the lower portion of the mixer itself is bent or warped this is a serious problem and will require you to dissassemble the entire unit. part number for the lower gearcase is 240350-4 Please not that all the parts list are white in colour. hope this helps.

Thanks

SOURCE: I have a KitchenAid Artisan stand mixer (325

the solution to this is to tighten the screw visible through the base that intersects the pin. Turn the machine upside down and using a long flat screwdriver tighten the screw.

SOURCE: my kitchenaid stand mixer arm wobbles when I turn

if the head wobbles on stand, flip mixer upside down, and tighten the pivot pin screw way deep down inside stand. you will need a long flat blade screwdriver. it's probably loose.