Former state attorney general J. Marshall Coleman of McLean is favored 3 to 1 over former Fairfax delegate Wyatt B. Durrette for next year's Republican nomination for governor, according to a new poll published today by the Richmond Times-Dispatch.

The poll, taken last week, showed, however, that just over half of the 463 respondents who identified themselves as Republican or leaning Republican were undecided, indicating that, seven months before the nominating convention, the contest is far from over.

In the same poll, of the 312 persons who identified themselves as Democrats or leaning that way, 62 percent were undecided.

Of the three potential Democratic candidates named, Lt. Gov. Richard J. Davis led with 22 percent, compared to 10 percent for current Attorney General Gerald L. Baliles and 7 percent for state Del. Richard M. Bagley (D-Hampton), chairman of the House Appropriations Committee.

Coleman, who lost a bid for governor in 1981 to Democrat Charles S. Robb, was favored in the poll by 35 percent, compared to 11 percent for Durrette. Durrette, now a Richmond lawyer, was the GOP's losing candidate for attorney general in 1981.

Coleman has been testing support for another campaign by contacting potential delegates to the party's convention and with limited appearances around the state. Under Virginia law, Robb cannot succeed himself.

Durrette's showing comes after more than a year of stumping the state to line up support among many party officials in an effort to lock up his nomination.

But the poll could fuel doubts about Durrette's ability to win a statewide race, according to some party leaders, some of whom favor other candidates.

"People do express the fear Wyatt can't win," said GOP national committeeman William Stanhagen of Manassas, who noted that Coleman lost his race in 1981. "I don't know why they think Marshall can . . . . " Stanhagen indicated he would support 8th District Rep. Stan Parris of Fairfax for governor if Parris runs. Parris is facing reelection to Congress next week and was not included in the survey.

Stanhagen, who has traveled across the state frequently, said he has found strong support for Durrette and Coleman but said he was surprised Coleman led Durrette in the poll.

Former congressman M. Caldwell Butler of Roanoke, who suspended his own bid for governor earlier this year, said the poll "indicates neither Coleman nor Durrette has been very successful. It's bound to put more pressure on former governor John N. Dalton," who ruled out running again even though he was virtually assured of his party's nomination.

The questions on the governor's race were tacked onto an overall survey of this year's presidential and Senate campaigns.

Coleman said yesterday that the new poll boosts his contention that he is the stronger candidate, while Durrette dismissed the results as name recognition for Coleman. Durrette said Coleman had served four years as attorney general and had run for governor while he had served as a local legislator and had run statewide only once.

"I have been out of office for three years," Coleman said, acknowledging that he may have been helped in the poll by publicity he received during the summer when he strongly criticized the state's Department of Corrections.

"That may be part of it . . . . It's always good news to be ahead," Coleman said. "You never hear someone ahead denigrate the polls."

Although the Democratic sample was much smaller, the poll indicated good news for Bagley, the least known of the three Democratic candidates despite his influential position in the legislature.

Davis and Bagley have openly said they are running for governor. Baliles, who defeated Durrette in 1981, has an active campaign committee to pursue the office but has not formally said he is running for governor, according to his aides.

Most of the potential candidates for governor are expected to file campaign finance reports today, although the state disclosure law allows some to be put off until January.