JACKSON, MISS., AUG. 3 -- State Auditor Ray Mabus is heavily favored among the eight candidates in Tuesday's Democratic gubernatorial primary, but history makes that a mixed blessing. Not since 1963 has the winner gone on to win the runoff.

Each of five Democrats is considered a strong contender to force a runoff against Mabus, who is running as a candidate of the next generation against "corrupt politicians and the Good Ole Boy network."

Tuesday's field, including two Republicans in the first contested GOP primary here since 1979, is a record crowd for the governor's race. Its size is due in part to a package of political, educational and economic revisions that strengthened the office in the early 1980s and allows the incumbent to run again.

The candidates see the opportunity to extend those reforms after four years of what they generally describe as stagnation under Gov. William A. Allain (D).

Their number and the fact that all 10 have stressed the same issues -- bringing jobs to the state and raising its education level -- may help explain the electorate's down-to-the-wire indecision -- 21 percent among Democratic voters, according to one poll, and 45 percent among Republicans.

Unless the leading Democrat wins a majority -- unlikely in a field this size -- he will face an Aug. 25 runoff against the No. 2 vote-getter.

In the Democratic primary, Mabus is well ahead in the polls, and his closest competitor appears to be former governor William Waller or Michael Sturdivant, a wealthy Delta planter and businessman.

The latest poll of likely Democratic voters by the Mason-Dixon polling firm shows Mabus with 31 percent, Sturdivant with 15 percent, Waller with 14 percent, Attorney General Ed Pittman with 11 percent, Mayor Maurice Dantin of Meridian with 5 percent, Jackson lawyer John Arthur Eaves with 3 percent and 21 percent undecided. Byhalia businessman H.R. Toney and Gilbert (Pete) Fountain, a Biloxi shipyard pipefitter, received negligible support.

The latest poll of the Jackson Clarion-Ledger and Daily News ranks the candidates identically but indicates a higher percentage of undecided voters.

On the Republican side, the Mason-Dixon poll shows Tupelo businessman Jack Reed, former chairman of the state Board of Education and a leader in education reform and school desegregation, swamping Doug Lemon, a financial adviser and planner. Reed was the choice of 48 percent of likely GOP voters and Lemon of 8 percent, with 45 percent undecided.

Among the Democrats, polls have shown Sturdivant and Waller gaining and Pittman, an early favorite to make the runoff, fading.

Waller, governor from 1972 to 1976, enjoys high name recognition and probably the best grass-roots organization.

Sturdivant has spent nearly $1.4 million -- some observers estimate it at closer to $1.6 million -- on his campaign, mostly in television. About $1.3 million of it was his own money, about the same amount he spent on an unsuccessful run in the 1983 gubernatorial primary. He has the support of Allain, who appointed him to the state Fiscal Management Board and relied on him increasingly as an adviser.

Mabus has raised and spent about $846,000, and Waller has reported raising about $400,000.

The black and rural white vote could be the key in the Waller-Sturdivant match-up. Waller is the only candidate who has stumped the small towns and pressed the flesh in the old-fashioned manner.

Eaves, however, proposes eliminating the personal property tax on new automobiles in a populist play for the rural vote, and Mabus claims considerable rural support because of his role in exposing corruption among rural county supervisors.

Sturdivant has spent a lot of money organizing and advertising in black areas and markets, but his efforts may be countered somewhat by Fayette Mayor Charles Evers, who has scolded black ministers and other leaders, saying, "we shouldn't be bought off."

Mabus is running as a generational candidate, pitting the future against the past.

Like the other contenders, he was attracted to the race by the reelection amendment, the elimination of legislators from executive boards such as the Budget Commission and the Board of Economic Development, and the 1982 Economic Reform Act aimed at improving public education.

"That's why I'm running," he said. "The people are ready, they're mad because we're at the bottom in per capita income and at the top in unemployment, and this is the best opportunity in a long time to get things done."

Waller, who with Democrats Dale Bumpers of Arkansas, Reuben Askew of Florida and Jimmy Carter of Georgia was in the first generation of progressive "New South" governors, agreed.

"I was ahead of my time and the legislative thinking of that time and I'm running this time because I saw an opportunity to break into futuristic programs," he said. "The new governor will have the opportunity to change priorities, to move more money into education and economic development, and with my experience and record, I can execute the plan."

Sturdivant is running as a businessman who will bring business efficiency to government. "Since I entered, everyone is running against the politicians," he said. "But I am a businessman, and I'll bring a new approach to solving problems."