NEW YORK--Sen. Henry M. Jackson (D-Wash.) took the New York Democratic primary yesterday with Rep. Morris K. Udall (D-Ariz.) finishing an unexpectedly strong second, despite Jackson's having outspent him three to one.

Jackson won a plurality of New York's 274 Democratic delegates, although he fell short of the majority he had predicted three weeks ago and again Monday. "We got our landslide, and we just missed a majority," Jackson told a crowed of about 150 supporters early this morning at the southern edge of New York City's Central Park.

With 90 per cent of New York's delegate votes reporting, Jackson led with 105, Udall held 71, 65 delegate seats remained uncommitted, and former Georgia Gov. Jimmy Carter garnered only 33 seats.

Some Jackson supporters admitted disappointment with the Senator's showing in New York, where he had concentrated his organization and personal campaign appearances, while spending more than a half-million dollars.

Matthew L. Lifflander, chairman of the Executive Committee of the Jackson campaign in New York, said "I think Udall's the winner tonight." Of Jackson's assertion that he would win a majority of New York's delegates, Lifflander said, "Oh, well, he made a stupid prediction."

"We've won a draw," another Jackson staffmember said last night.

In effect, New York held 39 separate elections yesterday, one in each congressional districts. New York's stringent and complex proceedures for getting delegates on the ballot made it impossible for the candidates to field slates in every district. Udall had slates in 37 and Jackson in 35, while challenges by the Jackson forces to petitions filed for Carter delegates left Carter with slates in only 27 districts.

Daniel Patrick Moynihan, professor of Government, led a slate of five Jackson delegates to victory in the Bronx. The sixth delegate elected in that district was the area's Congressman, Johnathan Bingham, who is pledged to Udall.

Jackson never made it to the hotel ballroom rented for his victory celebration. Instead he addressed supporters early this morning in the open air across the street, honoring a picket line of striking NBC technicans in front of the hotel.

Aids of the Washington Senator decided early yesterday evening to switch locations, setting off a flurry of activity as staff members transfered sound equipment, a New Orleans jazz band, and a red and white crepe-covered flat bed truck to the street outside the hotel.

Terry O'Connell, state campaign coordinator for Jackson, said last night the decision to honor the picket line was made "when he was born."

"He's never crossed a picket line in 63 years. He's not going to start now."

Rep. Bella Abzug (D-N.Y.), who was elected as a Udall delegate in her district, said last night at the jubilant Udall headquarters that the Arizonian's strong showing in New York resulted in part from key endorsements of Udall by the New York Times and the New York Post, strong delegate slates often headed by Congressman, plus active support from the New Democratic Coalition and other reform Democratic groups.

Jackson strength in New York was based partly on Jewish support for his stance on Israel and the Soviet Union's emigration policies, and partly on support from traditional Democratic politicians such as Mayor Abraham Beame and Queens borough president Donald Manes.

Initial returns showed Jackson doing well in suburban Long Island and Westchester County, and relatively poorly in upstate New York.

Former Gov. Jimmy Carter of Georgia, until last night the Democratic frontrunner, finished a poor forth in New York, well behind the Udall and uncommitted slates.

Many of New York's uncommitted delegates are supporters of Senator Hubert H. Humphrey (D-Minn.)