Morris Udall lumbered up the walk to last night's $250-a-person campaign fund-raiser for the Arizona Democrat's 1982 congressional race and, without a political audience in sight, launched one-liner No.1: "Do I need a ticket to get into this damn thing?"

"It depends," said the ticket-taker in front of the house of the host, General Motors heir Stewart Mott. "Who are you?"

One-liner No. 2: "Who else? Rev. Falwell."

Udall, who has served in the House of Representatives for the past 20 years and who challenged Jimmy Carter for the Democratic nomination for President in 1976, said, "I'm here to stir up a little business." Udall expects strong Republican opposition in his upcoming race and he tried to inspire the crowd of more than 200 with a stream of jokes aimed at conservative political foes:

"You know Rev. Falwell said every good Christian should oppose the nomination of Sandra O'Connor to the Supreme Court. To which Barry Goldwater, in his usual roundabout way, said what Jerry Falwell needs is a good kick in the a--. To which I reply that as a practicing Christian, Rev. Falwell will no doubt turn the other cheek."

Then Udall, an ardent environmentalist, took on Interior Secretary James G. Watt: "His idea of a wilderness area is a parking lot with no lines."

Finally, Udall made excuses for some of the missing guests, including Walter Mondale, John Anderson, Robert Strauss and Edward Kennedy. "You won't believe it," said Udall, "But after all these years, Sen. Kennedy is across the street trying to fillbuster."

Guests, including House Majority Leader Jim Wright of Texas, former secretary of transportation Brock Adams and Sen. Gary Hart (D-Colo.), moved about the Mott residence but couldn't get much air circulating -- it was sweltering, and Udall was the first to peel off his jacket. The Mexican menu, including tacos, guacamole and spicy chicken bits, gave no relief from the heat, but the Mexican beer and margaritas went fast.

Ella Udall, who said she was fasting to lose weight, seemed to fear the worst if her husband lost the seat he has held since 1961, when he became the last congressman sworn in by Sam Rayburn. "I wouldn't want to have to live with him if he lost," she said. National Conservative Political Action Committee chairman Terry Dolan has said he expects to traget Udall for defeat next year but the 59-year-old Udall expressed confidence while sipping a very green margarita. "They've targeted me before and we won," he said, referring to his convincing 1980 victory over Richard Huff.

"Mo's survived so far," said Wright. "In fact, last time he increased his margin."

Udall greeted Gary Hart enthusiastically and called him "one of my favorite senators." Hart, who has been mentioned as a potential darkhorse candidate in the 1984 presidential race said of the rumors, "It's premature. Right now I'm helping the party rebuild in the area of issues. But I don't know. I have no burning ambitions. On the other hand, what happens in Washington is that you get close to those who do succeed and you begin to think. . . ."

"Why not!" said someone nearby.

"Right," said Hart.

Udall said Kennedy and Mondale were "obviously positioning themselves for the 1984 race" but was adamant about his own presidential ambitions. "The answer is no, and my wife is a notary public," said Udall. "'ve said that if asked to run I'd run to the Mexican border, and if elected, I'd fight extradition."