This is the first time that I have heard of this particular problem with a Razor Crazy Cart so I suspect that it might have been damaged in shipping or in the store before you purchased it.
This sounds to me like it could be a bent axle or broken rim. The axle is made of steel and could be bent, and the rim is made of aluminum so it is brittle and more prone to breaking than bending. It could also be a problem with the tire or a problem with the way the tire was mounted on the rim. I recommend unplugging the battery pack from the cart so the motor can not run, and then turning the Crazy Cart on its side (preferable on a carpet so it does not get scratched) and inspecting the front wheel by turning it by hand and seeing if it is true or if it has a wobble to it. If the front wheel has a wobble then you should be able to get it replaced under warranty if the cart was purchased new.
Please let us know how it goes.
Mine also had the death wobble. I found the stem nut was not even close to tight.
Faulty wheel bearings must be a fairly common problem if Razor knew exactly what part you needed as soon as you mentioned the problem. I am interested to know if replacing the front wheel helps. Please let me know how it goes after you finish replacing the front wheel and have someone give it a test drive.