Have a mobile home and when purchased 17 years they sent me original title and there are no liens--already Checked with DMV--offered a payoff of less than what's owed due to hardship --they won't accept--if I don't pay can they sue for non payment as they are not on title and have NEVER BEEN ON TITLE

Yes. All the need is the loan documents, to sue in court. If it was over looked to add them on the title. That does not effect their ability to sue.

"They" can sue, assuming that the claim is not barred by an applicable statute of limitations. If they failed to perfect their lien on the MH, however, they probably won't be able to repossess the MH. Once they get a judgment against you, however, they could, if they so chose, execute upon the MH or upon other non-exempt assets you may own.