The difficult task of finding an unprejudiced jury for the trial of controversial South Korean evangelist Sun Myung Moon, accused of tax fraud, began today at U.S. District Court here with the impaneling of 200 jury candidates, quadruple the normal number.

But even before Judge Gerrard Goettel could query the panelists on substantive issues, 83 asked to be excused after the judge predicted the trial could last three months.

Defense attorneys are seeking a non-jury trial, a move opposed by federal prosecutors. Last week Moon's attorneys presented Goettel with a poll prepared for them by a public opinion researcher with Doremus & Co., seeking to show how unpopular Moon is.

Of 1,000 people polled in the New York area where a jury would be drawn, the poll found "76.4 percent responded unfavorably to the name Rev. Moon." After reviewing the poll, Goettel acknowledged that Moon "may be so distinctly unpopular that it is going to be impossible to get a truly fair jury." But Goettel said he'd spend a few days trying.

Moon, the 61-year-old founder of the Unification Church, was indicted last October for allegedly filing false income tax returns in the years 1973 through 1975. The 12-count indictment also charged Moon and a close associate, Takeru Kamiyama, with conspiring to defraud the government on tax matters. The indictment charges Moon with one count of conspiracy and three of filing false tax returns. If convicted, he could face up to 13 years in prison and fines totaling $25,000.

In addition to one count of conspiracy and two of aiding in the filing of false tax returns, Kamiyama is charged with a count each of obstructing the government's investigation and submitting false documents as well as four counts of perjury. If convicted on all nine counts, Kamiyama could face up to 41 years in prison and $75,000 in fines.

The government alleges that Moon failed to report to the Internal Revenue Service $112,000 in interest on a $1.6 million account at Chase Manhattan Bank, which was deposited in his name and which he used for personal and business purposes, and that he failed to report as income $70,000 of stock in a tea-importing company that had been given to him and his wife.

Defense attorneys say that the funds in question belonged to the church, not to Moon.

The American branch of Moon's Unification Church, which claims 4 million followers worldwide, is based here. Among the church's assets in the New York metropolitan area are a daily newspaper and an estimated $75 million in real estate.

Defense attorneys, pressing for a non-jury trial, presented Goettel with a long list of provocative questions for would-be jurors. The judge rejected some, toned others down.

Because of the sensitivity of some of the questions, the judge will do most of the interviewing of jury candidates in his cloakroom. They will be asked, among other things, if they are prejudiced against Koreans and if they would be upset if a church, and specifically a branch of Moon's, moved into their neighborhood.

Prosecutors argued that use of the word "moonie"--Moon's followers--be barred in jury selection because it is "a negative term." But the judge denied the request, calling the word "moonie" properly "descriptive."