With 18 months to go before New Yorkers elect a new mayor, the field of candidates emerging to succeed Mayor Bloomberg is failing to excite New Yorkers.

A professor of political science at Baruch College, Douglas Muzzio, said the problem is a lack of “star power” and “juice.”

“The conventional wisdom is that this is sort of an unexciting field,” he said. “I don’t know who out there would make it more interesting and engage the electorate. I don’t know. I don’t know if any of these folks can turn people on.”

On the Democratic side, there’s Rep. Anthony Weiner, an aggressive campaigner who has clashed with Mr. Bloomberg; Comptroller William Thompson Jr., whose own lawyer was recently reported to have derided the candidate in a courtroom, and the speaker of the City Council, Christine Quinn, who is embroiled in a budget scandal at City Hall that could derail her anticipated mayoral bid.

The lone Republican in the race so far, billionaire John Catsimatidis, has garnered little enthusiasm from political insiders, who are refusing to consider him “the next Bloomberg” despite his personal wealth and outsider status.

One sign of dissatisfaction with the field is the public’s fixation on the police commissioner, Raymond Kelly, who is fast becoming one of the most talked about figures in mayoral conversations. The only problem is that Mr. Kelly is not running and has offered no indication that he intends to jump in.

The mayoral hopefuls may be having a tough time because their campaigns have not yet begun in earnest, with the exception of campaign fund-raisers. New Yorkers also are likely comparing them to the popular sitting mayor, whose approval ratings have dipped below 70% only once in more than two years, according to Quinnipiac University.

A former top aide to Mr. Bloomberg, William Cunningham, said it sometimes is difficult for the public to imagine a political candidate in the seat they are seeking until they are there. He said it’s a common phenomenon for the public to be underwhelmed by the crop of presidential candidates at the start of a White House race.

“The same thing happens with mayor. La Guardia, Koch, Giuliani, now Bloomberg. He’s been there seven years and people have a feel for him,” he said. “They like a Koch, they like a La Guardia, they like that kind of feistiness, and you don’t see that from the other candidates.”

Mayor Koch, who long ago announced his support for Mr. Kelly, said yesterday that the call for “good candidates” to enter the race is growing, and said the public is not yet satisfied with the field.

“I believe people are constantly thinking of Ray Kelly,” he said.

Mr. Koch called Mr. Kelly, a “fitting successor” to Mr. Bloomberg, but noted that he thinks all of the candidates are good. He said none, however, have the broad base of support he would expect to form behind the police commissioner.

In March, Mr. Kelly came in first place in a poll of New Yorkers asked whom they would want to elect mayor in 2009, winning support from 22% of respondents.

Mr. Weiner tied for second place with the president of Brooklyn, Marty Markowitz, with 14% of the votes. Ms. Quinn garnered 13% and Mr. Thompson and Public Advocate Betsy Gotbaum both picked up 8%, according to the Quinnipiac University poll.

The university is expected to release a new mayoral poll today.

A political consultant who is not working for the mayoral candidates, Chad Marlow, said Democrats are nervous about their party’s field, which he said has grown weaker due to the announcement that the president of the Bronx, Adolfo Carrion, would run for comptroller instead of mayor, and because of the council budget scandal that is ensnaring Ms. Quinn.

“There is a lot less confidence there than there was six months ago, and if there is much more that comes up to damage the field, it will go from concern to panic,” he said. He said it is up to Messrs. Thompson and Weiner to “hold the line.”

“We can’t take any more damage to any more candidates,” he said. “At a minimum, the Dems need a competitive race between two quality candidates.”

A professor at Cooper Union who is a historian of Mayor Giuliani’s administration, Fred Siegel, said he didn’t think the council speaker had much of a political future, arguing that she’d been badly damaged by the council budget scandal. The U.S. attorney’s office and Department of Investigation are probing the council’s finances.

As for the rest of the field, he said it was too early to offer an assessment.

“I think the big question is, does Ray Kelly run, and if he runs does he run as a Democrat or a Republican,” he said. “The crop of candidates? It’s not something that most people have given much thought to whatsoever.”