Turkish Premier-designate Bulent Ecevit, who is to form a center-left government Thursday, said today that the United States should leave Greece and Turkey "alone to solve their problems."

Ecevit, 52, is a social democrat who is forming a Cabinet following months of political unrest and the collapse of the center-right government of Suleiman Demirel. He cautioned in an interview that he was not suggesting that the United States ignore the problems of its allies.

"But I am suggesting that they should not be overinvolved," he said.

The U.S. Congress imposed an arms and military aid embargo against Turkey following its 1974 invasion of Cyprus. The invasion was authorized by Ecevit, who was prime minister at the time. Congress' action, taken in hopes of forcing Turkey's withdrawal, soured this country's relations with the United States.

The action also "inceased the rigldity" of Greece, Ecevit said, "making our problems more difficult to solve."

Ecevit, who was premier for nine months in 1974, blamed the center-right governments that followed his for the impasse with Greece.

"They were governments with no foreign policy," he said.

Ecevit said the government he was setting up would "reactivate foreign policy in Turkey."

"We shall give priority to our problems with our neighbors, namely our problems with Greece, and to bringing about a final and viable solution to the Cyprus issue," he said.

On political violence and the financial crisis in Turkey - two key factors that led to the downfall of Pretical violence and economic turmoils have increased rapidly in recent months.

Thirteen of the 14 rightist and centrist legislators who have pledged their support to Ecevit's left-leaning Republican Peoples Party are expected to be given posts in his Cablnet. It is virtually certain that the president will ratify the new government and that it will win a vote of confidence in the National Assembly.

On Turkey's future relations with NATO and the European Common Market, Ecevit said: "We mean to continue our alliances and partnerships with our present allies and partners. But the starting point of all our international relations will be the historical and geographical reality that Turkey is a Middle Easten and Balkan nation."

The premier-designate said his government would seek better relations with all its neighbors, including the Soviet Union.

He said Turkey could provide the "missing link" between unused Middle East capital and Western technology and his government would welcome foreing investment in such "triangular" economic cooperation.

On Turkey's negotiations with the International Monetary Fund - for an emergency loan to help pay pressing foreign depts. Ecevit said standard IMF "recipes" were not applicable to Turkey and this should be taken into consideration.

Ecevit said all countries interested in the survival of democracy in Turkey should help the Turks over their present economic difficulties.

"After all," he said, "Turkey is the only developing country in which demoracy has survived since the second world war."