73-year-old Nigel Clayton was convicted of attacking seven young male victims between 1976 and 2017.
He would offer small amounts of money for odd jobs at his car garage to gain access to them, but would also offer gifts or hold debts over them.
He targeted boys with no relationship to their biological father, and would lie, saying he was a doctor or knew about child development.
Clayton has been sentenced to 30 years in prison.