WASHINGTON, Oct 21 (Reuters) – Paul Ryan tried to win over hard-line conservatives on Wednesday in his bid to become the next speaker of the U.S. House of Representatives as fellow Republicans quarreled over how to avoid an historic default on Washington’s soaring government debt.

Coming within days if Congress fails to act, a default could shake the markets and the economy, but the Republican-controlled Congress had no clear plan to prevent it, and was consumed by an intra-party power struggle expected to extend into next week.

Ryan, who ran for vice president in 2012, has said he will seek the top House job, which his party has struggled to fill, but only under certain conditions, including receiving the endorsements by Friday of conservative factions.

The nine-term congressman spent much of Wednesday in private meetings with these factions to try to nail down their support. He was scheduled to hold a crucial meeting in the late afternoon with the right-wing Freedom Caucus, a small but vocal splinter group of about 40 of the House’s 247 Republican members.

If enough Freedom Caucus members withhold their support, Ryan might walk away from the race to replace Speaker John Boehner, who is slated to retire on Oct. 30. Boehner has set Oct. 28 for Republicans to pick a nominee and Oct. 29 for the full House to vote for a new speaker.

The leadership struggle has dragged on since Boehner’s surprise retirement announcement in late September, even as a Nov. 3 deadline approached for Congress to act on the federal debt limit and a Dec. 11 deadline drew near for enacting new funding to keep federal agencies operating.

Underscoring concerns about these deadlines and the absence of any plan to confront them, U.S. Treasury Secretary Jack Lew said he feared a fiscal policy “accident” if debt brinkmanship continued as the country edged closer to a possible default.

For now, the House Republican leadership has not settled on when it would vote to raise the debt limit or what would be in a bill dealing with it. “We’re talking a lot about it right now,” House Majority Leader Kevin McCarthy told Reuters.

The only debt-related measure set for House floor action at the moment is one to be voted on later on Wednesday requiring the Treasury to keep borrowing to pay the principal and interest on certain obligations if the debt exceeds the statutory limit.

Democrats have blasted this legislation as ensuring Chinese bondholders get paid while many other government activities halt, such as payments for U.S. troops and veterans.

On the speakership struggle, Representative Marlin Stutzman, a Freedom Caucus member, said Ryan may have eased some conservatives’ concerns over a proposal he mentioned late on Tuesday regarding a long-standing rule allowing lawmakers to oust a sitting speaker.

Facing a backlash, Ryan on Wednesday clarified that he did not want to scrap the procedure, but instead modify it. He did this at a meeting of the Republican Study Committee, the largest conservative group in the House.

Even so, some conservatives such as Representative Raul Labrador, who want to protect the rule that allows a speaker to be ousted, were not soothed. “There was nothing there that changed my mind,” Labrador said after the meeting.

Representative Mo Brooks, a Freedom Caucus member, said Ryan’s desire to spend weekends with his family in Wisconsin, rather than raising money for his party, showed he would not be able to do the speaker’s job “as it is normally done.”

(Additional reporting by Andy Sullivan, Susan Heavey and Lindsay Dunsmuir; Editing by Kevin Drawbaugh and James Dalgleish)