The Sequoia, that long-lost symbol of presidential perks, is coming home.

A Florida-based group calling itself the Presidential Yacht Trust announced yesterday that it had purchased the 104-foot, mahogany-trimmed boat Jimmy Carter sold four years ago in a federal belt-tightening move. At the time, the cost ot taxpayers to maintain the boat was put at $100,000 a year.

The 56-year-old Sequoia set sail Monday for Washington, where it will be made available to President Ronald Reagan and also for social forums and events.

"They're not giving it to the government or the president; they're simply putting it back in Washington," said Dr. Jon Staiger, executive director of the Ocean Learning Institute in Palm Beach, which sold the boat for a little more than $1 million.

"It still has Harry Truman's piano and the presidential bed," said Staiger. "It hasn't been taken apart."

The Ocean Learning Institute has worked out an arrangement with the new owners to lease the Sequoia in the winter months.The chairman of the trust, Washington businessman Michael Doud ygill (a nephew of President Eisenhower), was on board the Sequoia last night and could not be reached for comment.Staiger said the Sequoia would arrive in Washington June 28 and would return to Florida by October.

ystaiger said the money to buy and maintain the Sequoia came from private donations. He would not elaborate on who or how many citizens comprise the group, which had been negotiating the purchase of the yacht for the last six months.

The nonprofit scientific institute purchased the Sequoia last year for $750,000. Staiger said yesterday they had spent nearly $250,000 on repairing the vessel. "Ever since we bought it, we've been trying to get some support in maintaining it. It's a fairly expensive proposition," he said. "We're not a yacht preservation agency."

"We recouped our investment," said Staiger.

In the last feew months, the Sequoia had been docked in Stuart, Fla., and open to the general public. "Rather than make it into a bar or a cocktail lounge, this group came along," Staiger said.

The boat was built in 1925 and became the presidential yacht in 1933. It was first used by Herbert Hoover after he sold a yacht called the Mayflower as an unnecessary luxury. President Franklin D. Roosevelt is said to have planned war strategy with British Prime Minister Winston Churchill on board the Sequoia. Lyndon Johnson installed a presidential bar. No other president enjoyed escaping on the Sequoia as much as Richard Nixon, who made 53 trips up and down the Potomac during the Watergate scandal. President Ford, by comparison, made only four trips.

White House deputy chief of staff Michael Deaver, who had been handling Reagan's search for a presidential yacht, could not be reached for comment. A spokesman in his office said they were unaware of the Sequoia sale.