If you have no health insurance and need to go to the ER, will they treat?

Yes. Only in an emergency

Every hospital in the event of a life threatening situation has to stabilize you to get you to an appropriate facility if they can't treat you, they are a level one facility so they should be able to treat you what ever the injury. But bear in mind its not a free treatment. Be considerate of the staff's hard work and make arrangements to pay your medical bill. Not sure if it applies to non emergent treatment, they can evaluate that. But its better if you to a 24 emergency clinic if it isn't a life threatened situation.