SALEM – A Boston mechanic who admitted stealing $50 from his cousin at knifepoint in Lynn last year was sentenced to five years in state prison to be followed by four years of probation.George Walker, 42, of 80 Bismark St., Boston, made his plea Wednesday in Salem Superior Court, pleading guilty to armed robbery as well as witness intimidation before Judge Timothy Q. Feeley.Feeley adopted the joint recommendation suggested by Assistant District Attorney Greg A. Friedholm and defense lawyer Randi Potash.The charges arise out of an incident on Nov. 9, 2010 at 3:30 p.m., when Walker robbed $50 from his then 23-year-old cousin at knifepoint on Western Avenue.Then, three months later on Feb. 14, Walker, along with his female friend, Jamie Lee Duncan, tried to get the victim to sign a document stating the robbery never happened, all while threatening him with bodily injury.Duncan, 25, of 41 Story Ave., Beverly, pleaded guilty to a charge of intimidation and was given a suspended one-year term to the House of Corrections and placed on a year of probation by Feeley.Potash said the plea was the result of “extensive negotiations” and, as conditions of their probationary terms, both were ordered to have no contact with the victim.The judge credited Walker the 295 days he spent in jail awaiting trial on the case.The couple was indicted by an Essex County grand jury last March.