An intense effort by Montgomery County executive candidate Sidney Kramer to entice three County Council incumbents and several other council hopefuls to his Democratic campaign has collapsed six months before the party's crucial primary election, according to Kramer supporters.

The decision by six council candidates to spurn Kramer's request that they join him on a ticket marks the first significant setback in Kramer's well-financed and organized bid to become Montgomery's next executive.

"Sidney put most of his eggs in this basket," said one Kramer strategist, referring to the local Democratic tradition of running slates of candidates in primary elections. "Now the whole thing has blown apart."

Kramer, who is locked in a bitter race with council member David L. Scull for the executive post, and Kramer campaign advisers had worked for weeks courting council veterans Rose Crenca, Michael Gudis and Neal Potter, as well as political newcomers Bruce Adams, Isiah Leggett and Michael Subin, all Democrats.

On Feb. 23, at a private meeting at the home of Keith Haller, a Montgomery political consultant and pollster, most of the six council hopefuls indicated they were willing to join a Kramer ticket, according to several who were present.

But on Saturday, in a six-hour meeting at Leggett's home, the apparent unanimity collapsed and the six canceled another meeting that was scheduled for the next day, again at Haller's home.

"My preference is that there be an independent slate," said Leggett, a black whose distinguished military service and professional record made him the object of intense lobbying by both Kramer and Scull.

David Robbins, a Democrat and the county government's recreation director, and Republican Albert Ceccone also are running for the executive post.

No black has ever been elected to the County Council, the seven-member legislative arm of Montgomery's local government, and Kramer looked to Leggett to provide some racial balance on the planned six-member slate. Potter, who has served on the council longer than any other person, could have lent his considerable stature to the slate, while Subin, a Gaithersburg resident, could serve as a voice for the fast growing area in upper Montgomery.

Several of the six council candidates, who spoke on the condition that they not be identified, said Kramer's request was rejected mainly because the group believes it would be easier to get elected if it stays out of what is shaping up as a bitter fight between Scull and Kramer.

Kramer, for his part, was philosophical about the decision.

"It's their decision to make, and I respect it," said Kramer, a state senator from Silver Spring. "I never had a formal commitment from them."

However, Kramer's own advisers, who believed the six had committed to their candidate, were thunderstruck. One of them, Gilbert B. Lessenco, angrily confronted Bruce Adams on Sunday night at a gathering of more than 500 Democrats in suburban Baltimore.

Adams declined comment yesterday, saying he did "not want to stir the fires that are flaming."