Florida developer Stuart S. Golding missed a deadline yesterday to have guaranteed financing arranged and begin construction on a $90 million restoration of the Willard Hotel, a cornerstone of plans to revitalize Pennsylvania Avenue and Washington's old downtown.

Directors of the Pennsylvania Avenue Development Corp., which owns the property and is coordinating the redevelopment of the avenue, scheduled a meeting for Wednesday at which the board could declare Golding in default of his lease.

If the board rules that Golding, who has had a series of problems in arranging financing for the restoration, is in default, he still would have 90 more days to obtain the financing and begin work before losing his lease.

But the missed deadline raises new questions about a project that is supposed to anchor the Western end of a wide swath of downtown Washington that is slated for redevelopment.

Kenneth A. Golding, the developer's son who handles his affairs in the Washington area, declined to comment yesterday on the passing of the deadline. Sunday actually was the deadline, but it was extended to Monday because Sunday was not a business day.

But although Kenneth Golding would not say yesterday whether financing has been arranged, Stuart Golding complained last month that he was having trouble putting together the deal.

"I haven't found the permanent financing I need, nor do I expect to in this climate," said Stuart Golding last month. "Where are you going to get cheerier news when the prime rate is 19 percent?"

Golding has had a small crew inside the ornate old hotel at 14th Street and Pennsylvania Avenue for several weeks working on the upper floors, but that does not fulfill the terms of the contract, said attorney Max N. Berry, chairman of the Pennsylvania Avenue Development Corp..

Earlier this year Golding attempted to secure $20 million in funds from the federal Urban Development Action Grant program to round out his financing package. Mayor Marion Barry and the City Council approved the request, but Barry declined to pass it along to federal officials after questions were raised about using the grant money to subsidize the renovation of a luxury hotel. Rival developer Oliver T. Carr Jr. offered to do the job with no federal aid.

Stuart Golding last month accused Carr of trying to block his project. Golding originally won the lease on the Willard over a proposal by Carr to handle the redevelopment.

After being chosen as developer of the project in 1978, Golding repeatedly sought to delay the work, citing high interest rates and soaring construction costs that were driving up the price tag.

Kenneth Golding said in February that he and his father were "confident" of being able to arrange private financing for about $70 million of the total $90 million cost of the project. He said, however, that if the additional $20 million could not be found, "a lot of cuts" in the project would be required.

He described the planned cuts as being in the finishing materials and amenities of the hotel. Berry said yesterday that he understood Golding planned to try to reapply for the federal UDAG grant.

The ornate old hotel, located across Pennsylvania Avenue and the new Pershing Park from the Commerce Department and the District Building, once was one of the city's finest hotels. Its revitalization is designed to provide new top-quality hotel space downtown and complement nearby redevelopment projects, such as Carr's new shopping complex at 15th and F streets NW and the National Press Building development directly across 14th Street.