CORPUS CHRISTI, TEX., JUNE 26 -- Rep. Jack Kemp (R-N.Y.), in what he described as a "lonely adventure" before an overwhelmingly Democratic audience, evoked a stronger response than two Democratic presidential hopefuls today in a speech to the country's largest Hispanic organization.

Addressing the national convention of the League of United Latin American Citizens (LULAC), Kemp pointedly noted that he was the only candidate for the 1988 Republican presidential nomination to accept an invitation to speak here and went on to chastise his party for abandoning its founding principles.

"Somewhere along the way, my party blundered," Kemp said. "It strayed from the principles of Abraham Lincoln. And I hope today to lead it back to those principles. I want my party to be a Lincoln party, not a Hoover party."

By Sunday, all seven of the announced Democratic presidential candidates will have addressed the convention. Kemp's decision to be the lonely Republican here was in keeping with his longstanding insistence that the GOP must broaden its base if it is to become the nation's majority party.

Judging by the audience's reaction, Kemp more than held his own following speeches earlier today by Democratic hopefuls Sen. Albert Gore Jr. (Tenn.) and Massachusetts Gov. Michael S. Dukakis.

"Certainly he improved his standing," said Ruben Bonilla Jr., a Democrat and the convention chairman.

Bonilla added that when LULAC officials complete an informal canvass among the 3,000 delegates at the close of the convention Sunday, "I would not be surprised if Kemp scores higher than some of the Democrats."

Dukakis delivered half of his speech in Spanish, which he learned as a college student in Peru. He stressed the economic gains Massachusetts has made under his administration and his heritage as the son of Greek immigrant parents. He pledged to end "the lingering curse of racial and ethnic discrimination -- whether it is in our communities or the administration of our immigration laws."

Gore said, "The Hispanic agenda is America's agenda, and the first item on that agenda is jobs." He also criticized the Reagan administration for "an incredible blind spot in failing to recognize how important the future of Mexico and Latin America is to the future of the United States."

All of the candidates pledged major federal commitments to education and emphasized the importance of family values, themes that struck a responsive chord in the largely middle-class organization.

While Kemp clearly impressed the LULAC delegates today, his performance did not obscure the hurdles facing any Republican hopeful in the Hispanic community.

William C. Velasquez, president of the Southwest Voter Registration-Education Project, said he expected Hispanics to account for at least 20 percent of the Texas Democratic primary electorate next year. In contrast, Hispanics were less than 2 percent of the Texas Republican primary turnout in 1986 and will probably account for about the same in 1988, Velasquez said.

Moreover, LULAC officials said there is a deep disillusionment with the Reagan administration in the Hispanic community that is certain to be exacerbated by the refusal of all of the GOP candidates except Kemp to appear here. Vice President Bush, who declined for the second consecutive year to address the convention, appeared to have been damaged the most, according to Jorge E. Rodriguez, special assistant to LULAC President Oscar Moran.

Moran, a San Antonio Republican who campaigned for the organization's presidency by promising to provide a bridge to the Reagan administration, also expressed "disappointment and disillusionment" with the failure of Bush and the others to appear.

"If the Republican Party hopes to increase the gains it has made in recent years, this type of response is not going to enhance that process and may reverse it," he said.