American U.N. Ambassador Andrew Young ended a two-day visit here today after assuring Prime Minister Michael Manley that the United States respects his efforts to steer Jamaica along political and economic paths that Manley calls "a third way" between capitalism and communism.

U.S. official's accompanying Young said the Carter administration, in an attempt to match this pledge with deeds, is putting together a package of increased financialaid for the troubled Jamaican economy.

If Congress approves, the officials said, U.S. assistance to this Connecticut-sized island of 2 million people will jump from its current level of slightly more than $10 million to between $50 million and $60 million through the 1975 fiscal year.

The first part of this package, a $12 million agreement covering surplus food sales, will be signed Monday. The officials said that other parts of the program, which are still being worked out, are expected to include technical assistance and development projects in the fields of agriculture and education and a $10 million commodity import loan that will enable Jamaica to purchase badly needed equipment such as machinery for agricultural cooperatives.

Young's visit - along with the behind-the-scenes negotiations on increased aid - is intended to symbolize the Carter administration's determination to improve relations with Jamaica and put a new high priority on increased cooperative with all the countries in the Caribbean.

Young, who left here this morning for an overnight visit to Mexico, pointedly made Jamaica the first stop on his 10-nation Caribbean tour. Young has frequently visited Jamaica and emphasized his personal affection for the country and its people.

At a meeting with university students yesterday, he summarized his feelings by recalling that he first came to Jamaica two decades ago when he was a young civil rights leader in Georgia "where blacks were not allowed to vote or do hardly anything."

He was emotionally overwhelmed," Young added "to land in Jamaica and have my passport stamped by a black official and then go out and see black policemen and black clerks running the banks." He added: "It was the first time I'd been anywhere where I saw black people running anything."

Young's affection for Jamaica has not been universally shared in official. Washington during the past few years, however. The problems have stemmed from Manley's program of "Democratic Socialism," which emphasizes an activist government role in running the economy and increased worker participation in the ownership of industry and agriculture.

Manely's policies also have included a strong emphasis on nationalism and an outspoken identification with the Third World that brought him into close friendship with Cuban President Fidel Castro. That has caused Manley's domestic political foes to charge him with trying to move Jamaica into the Communist orbit.

These fears were shared by some U.S. officials during the Nixon and Ford administrations, and Washington was especially annoyed last year when Manley publicly supported Cuba's intervention in the Angolan civil war. Some of the prime minister's supporters, in turn, have accused the U.S. Central Intelligence agency of trying to "destabilize" the Manley government.

Young, the Carter administration official most closely identified as sympathetic to Third World aspirations, has argued that Manley, whom he has known for years, is not a Communist and that his government should be allowed to go its own way and be given help to overcome its economic difficulties.

YThe Jamaican economy, traditionally plagued by high unemployment and a galloping birth rate, has been particularly depressed for the past year because of a big slump in bauxite, sugar and banana exports and the flight of domestic and foreing investors frightened by Manley's policies.

Tourism, normally second only to bauxite mining as the island's biggest scarce of employment, also has been badly hurt by reports of political unres. During the severe American winter, when most Caribbean resorts were doing a booming business, Jamaica's surfeit of luxury hotels had the lowest occupancy rate in the island's history.

In the course of a year, Jamaica's foreign exchange reserves slipped from a surplus of $55 million to a deficit or more than $120 million. To get help from the International Monetary Fund, Manley was forced to impose a tough asuterity program and cut some of his more ambitious plans for government intervention in the economy.

U.S. officials said that Manley told Young that the gap between haves and have nots in Jamacia's is too great to be bridged by capitalism. He also added that while he belives Jamaica has "much to learn from Cuba" he is not and "could never be a Communist."