Hugh L. Carey, New York's mercurial, outspoken governor, today announced that he will not seek a third term. The decision ended months of speculation fueled by polls that show his popularity at an all-time low.

Speaking at a noon news conference at the governor's mansion in Albany with his wife at his side, Carey, 62, a Democrat who served 14 years in Congress, cited personal and political reasons for his decision.

"You have all followed me long enough to know that I'm more of a fighter than a politician. Political polls never stopped me from saying what was in my mind, or from fighting battles I knew had to be fought," Carey said.

Nonetheless, he continued, "I have decided to devote all my strengths to finishing the work of the past seven years . . . . I cannot fulfill this commitment and at the same time immerse myself in the day-to-day details of the campaign trail. Therefore, I will then neither seek nor accept the nomination for governor."

A controversial politician whose un-politic remarks have sometimes landed him in hot water, Carey had had a troubled year. His marriage to multimillionaire Evangeline Gouletas, part owner of the controversial American Invsco, a Chicago-based condominium corporation, and his courtship of Gouletas at a time when many felt he should be involved in more serious matters such as a pressing budget cut, helped earn him the sobriquet "Society Carey."

His off-the-cuff commentary--he once dubbed the Senate seat of Jacob K. Javits the "Jewish seat" -- also hurt him. "I'm the victim of my own flip statments. It's my incautious Irish humor -- I better not blame the Irish -- let's say incautious Carey humor," he once told The New York Daily News.

That newspaper found his popularity last October at an all-time low. In another poll, by NBC-Associated Press, 46 percent said they felt Carey's marriage had hurt him. Carey's reluctance to subject his wife to possible attacks during a rough campaign apparently was a factor in his decision not to run.

"He's willing to put up a fight," said a source who is extremely close to Carey. "But he ever doesn't want to have a fight that involves his family."

Carey insisted that his poor showing in the polls was not the reason for his decision.

"Every poll I've ever taken before I begin a campaign I've always been the underdog," Carey cheerfully told The Washington Post after his news conference. "In '78, my opponent led by 40 points going into the polls. It's nothing new to me."

His decision has spurred discussion that he may make a bid for the presidency or seek other office. Carey, however, says he's "never had any interest in the presidency."

"I don't mean to sound frivolous," he said today, "but when I left Washington I felt I was leaving a town with no delis and no good bakeries--I'm a New Yorker. If they would reverse the Capitol between Washington and New York, maybe I would reconsider."

Even while a congressman from 1960 to 1974, the Brooklyn-born Democrat seemed more interested in the affairs of his home city and state than in national issues. His congressional record was far from stunning. Despite his abilities to hold an audience, he was intensely private and family-oriented and earned a reputation as a loner without close political allies or personal advisers.

In recent years, as his interest in being governor appeared to wane, he passed up or fumbled chances to lead a coalition of northeastern states, whose eroding industrial base and deteriorating older cities are being pinched by high energy prices and a waning commitment from the federal government.

Carey made an ill-fated try at the New York mayoralty in 1969, but gave it up, partly because of a personal tragedy when two of his sons -- Hugh Jr. and Peter--were killed in a car crash.

In March, 1974, Helen, his wife of nearly 30 years, died after an agonizing five-year battle with cancer. Days before her death, she urged Carey to fight for the Democratic gubernatorial nomination.

Carey, a virtual political unknown outside his Brooklyn district, hired consultant David Garth, lost 30 pounds and, with his dozen surviving children, took off on a primary campaign against the favorite of the regular Democratic Party, Howard Samuels.

Samuels--a well-known New York politician who then was head of the state's Off-Track Betting venture--was a lackluster campaigner, and Carey's Irish charm and wit, his family, a well-orchestrated television campaign and his distance from the regular Democratic Party overcame Samuels' big initial lead.

Carey's first term was highlighted by a successful rescue of New York City from the jaws of bankruptcy, but was marred by severe infighting within his administration. Carey dipped low in the polls, but relied on his consummate campaign skills and a first-term record to ward off a 1978 primary challenge and go on to easy victory in the general election.

But his perceived lack of interest in governing--an issue in 1978--has increasingly alienated both professional politicians and voters.