Gov. John Spellman today called the Washington Legislature into special session Saturday to enact a bill that would establish an Oct. 11 special primary to nominate candidates for the U.S. Senate seat vacated by the death of Democrat Henry M. Jackson.

Spellman met with leaders of the state House and Senate today to draft the bill.

It would establish a three-day candidate filing period, Sept. 14, 15 and 16, with withdrawals allowable until 5 p.m. Sept. 19. A Nov. 8 special election already had been ordered by Spellman; state Democrats had gone to court seeking a primary to nominate candidates.

A Republican, Spellman said he had expected the state Supreme Court to order a primary election, as urged by the Democrats. However, when the court today refused to, Spellman called legislative leaders to his office.

He had consulted earlier with newly appointed Sen. Daniel J. Evans and Evans agreed with him that there should be a primary before the special election.

Meanwhile, Seattle Mayor Charles Royer, a liberal Democrat who is in his second term, today appeared to be emerging as a leading candidate to take on Evans in eight weeks.

Evans, a liberal Republican and former three-term governor, was appointed to the Senate Thursday by Spellman.

Evans will be sworn in Monday in Washington, D.C.

The winner of the Nov. 8 special election will serve the remaining five years of Jackson's term, which expires in January, 1989. Jackson was the patriarch of the Democratic Party in the state, and Democrats fear the seat he held 31 years may be lost to the Republicans if it is not regained by the Democrats in November.

National Republicans plan a strong financial effort to get Evans elected, but the Democratic Senatorial Campaign Committee backed away from making any financial commitment to the race unless the Democrats can agree to field a single candidate.

Royer met today with two potential Senate Democratic candidates, Rep. Norman D. Dicks and former congressman Brock Adams.

Both Adams, a six-term Seattle congressman and former secretary of transportation, and Dicks announced that they would not run. Adams, Royer, and Reps. Dicks and Mike Lowry are considered to be the strongest potential candidates against Evans.

Lowry today indicated that he will file as a candidate. "Those who are so sure Charlie is the best candidate are wrong," Lowry said. "They don't know what they're talking about."

Adams attended Jackson's funeral Wednesday, then consulted with party leaders and the other potential candidates before returning to his home in Washington, D.C.

"I could win the race," Adams said, adding that his decision not to run was a "family decision."

"I have devoted most of my adult life to public service and the elective process, but ambition is no substitute for family," he said.

Dicks said he would not enter the race because he feels he can do more for the state by staying in the House. He serves on the Appropriations Committee.

Reps. Don Bonker and Al Swift also were mentioned as potential candidates.