With only two weeks left until Boston's October 11 preliminary mayoral election, a clearer picture has emerged of which two candidates will compete in the November 15 runoff.

A poll conducted for The Boston Globe last week placed three candidates--David I. Finnegan, Raymond L. Flynn, and Melvin H. King--in a dead heat, and two others--Dennis J. Kearney '72 and Lawrence S. DiCara '71--more than 10 percentage points behind, in the eight person field.

And candidate Robert R. Kiley, whose campaign had floundered from the start, withdrew from the race last week, throwing his support to DiCara.

The poll, analysts say, for the first time raises the possibility that Finnegan--long considered a shoo-in for the final--may finish third and fail to make the runoff. The former School Committee chairman and WBZ-radio talk show host has been hurt because many voters feel his campaign lacks substance.

Early Finnegan campaign billboards featured the now famous slogan, "Finnegan or Him Again," referring to four-term Mayor Kevin H. White. After White announced last May that he would not seek reelection, the slogan became "Begin Again with Finnegan."

Finnegan's current TV spots feature scenic views of the city with the candidate recollecting his local roots.

Play It Safe

"David had a bad start with sloganeering," David M. Irons, a longtime observer and participant in Massachusetts politics who is director of external affairs at the Kennedy School, explained yesterday. "[Finnegan] figured a safe campaign offending no one is the best way to win. In a close campaign it doesn't pay to play it safe."

While Finnegan, the most successful fundraiser of the eight candidates, can afford a steady stream of television advertisements, the less affluent contenders are planning different strategies for the upcoming two weeks.

King, a former state representative who is the only Black candidate in the field, has started radio advertisements and plans to air one television spot before the preliminary, Media Coordinator Marsha Waters said yesterday.

King's campaign has gained quite a bit of momentum through a voter registration drive--similar to that undertaken by Chicago Mayor Harold Washington last year. Visits this summer by Washington and Atlanta Mayor Andrew Young have also helped improve his poll standings overall and among Blacks.

Moreover, according to Waters, potential presidential candidate Rev. Jesse Jackson, considered the nation's leading Black spokesman, may visit Boston to endorse King in October before the preliminary.

City Councilor Flynn has also shown momentum despite a money shortage so severe that Flynn told the Globe "I have nothing." The Globe reported yesterday that Flynn, who is paying for the education of his six children, was forced to borrow $16,000, halving his net worth.

Nonetheless, Flynn spokesman Frank Costello said last week that the campaign strategy will remain unchanged. Though Flynn will probably not be able to afford TV time, Costello said he will present 16 "major" program proposals in the next two weeks.

Flynn also appears to have weathered attacks during public forums and in the Phoenix on his past record. Flynn endorsed losing gubernatorial candidate Edward J. King last year and during the busing crisis in the 1970's proposed a state law abolishing compulsory education.

DiCara's spokesman Marty Bauman said yesterday that campaign workers are conducting a "massive" literature drop at 125,000 homes throughout the city.

Battman called DiCara's chances "very realistic." citing increased money contribution following the Kiley endorsement Wednesday.

Kearney, who has been buying TV time for a month, will conduct an extensive phone campaign, to be followed by mailings, spokesman Gregg Wilson said yesterday. Wilson added that the campaign, which is considered by many to be the best organized in the field, will try to bring many as 35,000voters on election day.

An informed source wins is not involved in the race said yesterday that Kearney campaign organization is better than that of Mayor White "at his height,? The source who asked not to be identified, added that Kearney was the only local politics who was able to provide campaign workers last year for the election bids of Governor Michael S. Dukakis and Congressman Barney Prank `61 (D-Mass.)

"Kearney is the most underestimated candidate out there," said Irons, adding that the media may be discounting Kearney because of his young age--he is 33.

And while both DiCara and Kearney trail badly in all recent polls, the potential is there for one or the other to sneak up behind the leaders. Polling has also shown that support for the leaders is "soft," meaning that voters may not remain loyal.

For the remaining three candidates--City Councillor Frederick C. Langone, Socialist Party candidate Eloise Linger, and Lyndon H. LaRouche disciple Michael Gelber--support appears scanty