A 27-year-old former Internal Revenue Service accounting technician pleaded guilty here yesterday to embezzling more than $140,000 from the government over three years by submitting fraudulent vendor invoices that resulted in payments in his wife's maiden name.

Sources said the embezzlement by Robert G. Lohr of 7273 Sheila Turn, Clinton, was discovered accidentally in April when a clerk in the IRS' national accounting office here had to process some checks manually.

Lohr, who held a GS7 grade, pleaded guilty to embezzlement and mail fraud before U.S. District Judge Stanley S. Harris, who set sentencing for Nov. 18. Lohr could be sentenced to 15 years in prison and fined $500,000.

Assistant U.S. Attorney Deborah Young said in court that Lohr submitted the first of 44 fraudulent invoices on July 30, 1984, for $995.57. The largest of the invoices was for nearly $5,000. Young said Lohr has already made "substantial restitution," and has promised to repay the rest of the money. Sources said he has paid back about $70,000.

Sources said Lohr had the checks mailed to the home of his wife's parents, and went to their home during his lunch hour to collect the checks from their mailbox without their knowledge.