"There are going to be excesses" in a "large-scale covert operation" such as the one the Central Intelligence Agency is conducting in Nicaragua, former CIA director Adm. Stansfield Turner said yesterday.

Adding to that probability, he said, was the Reagan administration's recall of "a lot of oldtime CIA employes" to run the operation. "Some of them have not been able to adapt to the restrictions in the new oversight process," Turner said at a breakfast with reporters.

Although he believes that under his successor, William J. Casey, the CIA has become "politicized" in its intelligence analyses and has "overemphasized" covert operations, Turner said he does not "think it is out of control that much" compared with the past. He recalled that in the 1950s and 1960s, agents running CIA covert operations sometimes "deliberately" misled the director about their activities.

Turner began his discussion of "excesses" with the recently disclosed CIA pamphlet for guerrilla operations in Nicaragua. The booklet calls for kidnaping officials of the Sandinista government and arranging the deaths of guerrilla members to create martyrs.

"At least one CIA contract employe did not understand the rule change" that says "don't do assassinations," Turner said. He added that he doubted that approval for the pamphlet was taken very high in the agency, saying it was "conceivable the director did not know of the manual."

He also described the situation in Nicaragua as "an overt covert operation" because of all the publicity surrounding it. "You should operate differently when you are under scrutiny," Turner said, indicating that he thought that the administration had not learned that lesson.

"You can't keep an operation covert," he added, "when it is controversial in the body politic."

In a broader sense, Turner said the administration has "overemphasized" covert operations, promoting some "that were not important to national security."

When he took office in 1977, Turner said, "there was no meaningful covert action under way" because of the backlash from earlier publicized CIA failures in Cuba and in Chile.

"We had a substantial number of covert actions under way before we quit," Turner said, but he criticized the Reagan administration for adding to that number.

In explaining the present trend, Turner said: "To the degree that the country has gone to the right, there is a greater acceptance . . . that we should do dirty tricks around the world to preserve our position."

He noted published reports that covert operations had been undertaken in Mauritius and Suriname. Turner said he "had surveyed," while CIA director, "some of the places where this administration has gone in." He said he had decided not to attempt some operations because the need was not that great or "the chances of success were not overwhelming."

Turner backed up his criticism of Casey's supposed "politicization" of the CIA by citing the recent resignations of two analysts who maintained that their findings had not been accepted because they went against administration policies.

On the other hand, he said he has "sympathy" for Casey on this issue because "sometimes analysts don't understand" that the director does not have to accept the opinions of analysts.