[RWebb]

in some states, that is implicit

what are the terms of your WRITTEN contract with him?
(PLEASE, don't say there isn't one!)

generally, you cannot neglect his property - i.e. stick it out in the weather and let it rot

you CAN usually charge for storage & can certainly stop work

what oral conversations have you had so far?

what written notes have you sent him beyond the contract?
- i.e. "hey, Mr. Smithers - Great news! I have your car 50% done. But, just a note - I need a progress payment of $xxx before going any further."