New York Democrats, ralling to the mystique of another Kennedy campaign, pledged $46,000 tonight to help their increasingly less reluctant champion in the first test of the 1980 campaign.

Sen. Edward M. Kennedy's stream of hints that he will challenge President Carter next year drew an overflow crowd to the event. The co-hosts, state Attorney General Robert Abrams and New York political figure William Woodward, began organizing the $250-a-head fund-raiser three weeks ago, but half the acceptances came in during the last four days, according to Ethan Geto, an aide to Abrams.

No elected officials except Abrams and none of the glamorous figures of past Kennedy campaigns came to Woodward's upper East Side apartment, but the anticipation of headier times to come fueled the hopes of many guests who spoke of "getting in on the ground floor."

The organizers had hoped to raise $25,000, but easily exceeded their goal with the help of a $10,000 contribution from painter Georgia O'Keeffe and her sister, Mrs. Robert B. Young, and $3,000 from Woodward, a wealthy young Democrat whose losing 1978 campaign for a state Senate seat cost almost $500,000.

In a new twist in the script of presidential politics, the money raised tonight in New York will be spent miles away in the Oct. 13 Florida Democratic caucuses that will have no direct bearing on delegate selection to the 1980 Democratic convention.

"One month from today, history will be made," the leader of the Florida draft-Kennedy forces, Micahel Abrams, said in thanking the New Yorkers for their support.

Abrams and other Kennedy backers have emphasized Carter's strength in Florida, claiming it is one of the president's strongholds, a state bordering his native Georgia and one which he has visited many times.

Mark Siegel, a former Carter aide who now supports Kennedy, said Kennedy will have to win a majority of the 870 Florida state convention delegates selected in the caucus to be seen as a winner. "I think we can do it," he said.

"We'll see who'll whip whose ass," Michael Abrams said, echoing the language of Carter's widely reported pledge earlier this year to defeat Kennedy if the Massachusetts Democrat enters the race.

But harsh language was the exception tonight. In speeches and in private comments during the sweltering evening in the barely air-conditioned apartment, Kennedy supporters spoke of Carter with words of faint praise.

"This gathering was born out of disappointment," Robert Abrams told the roomful of people, most of whom, like himself, supported Carter in 1976. "We and millions of Americans feel that President Carter is an eminently decent man with good instincts, who works hard and tries, but somehow it isn't working."

Michael Abrams, who also worked for Carter in 1976, said his Florida group had raised about $50,000 before tonight. The gifts from the New Yorkers bring the Floridians close to the $120,000 Abrams said they have budgeted for their effort.