A 20-year-old Mansfield man was sentenced to four years in prison this morning for the armed robbery of the Mobil gas station in Voluntown on Aug. 3, 2010.

Isaac Watson had pleaded guilty in April to second-degree robbery. According to state police, Watson and a codefendant, Bryan Carbonneau, covered their faces with bandannas, entered the Main Street business, pointed BB guns at the clerk and demanded money. They each reached over the cashier’s counter and took money from the register, totaling $400.

Carbonneau has also pleaded guilty and is scheduled to be sentenced May 30.

Watson has pleaded guilty to a similar robbery in Willimantic and is scheduled to be sentenced on Friday. Prior to the robbery charges, he had only been convicted of breach of peace.

Prosecutor Lawrence J. Tytla said Watson was not responsive during presentencing interview and is at significant risk of reoffending. Watson’s attorney, Peter E. Scillieri, said his client knows he has to address his substance abuse and emotional issues.

“We hope you turn it around, or you’re just going to spend the rest of your life in and out of jail,” said Judge Patrick J. Clifford.

Watson will be on probation for five years after he is released from prison.