in Missouri you need a title, everyone keeps talking about their own states but in MISSOURI you need a title. (for any gas motor I think) If you do not have one you need a Bill of Sale from person you bought from and have to have Missouri Highway Patrol (which are now part of Water Patrol) to run a check on it for a stolen motor unless the motor was once titled in you name in which case i believe you can file a lost title with the DMV. If a seller will not give you a BofS then it is most likely not theirs to sell.