WASHINGTON — Under fire from conservatives, House Speaker Kevin McCarthy worked strenuously Tuesday to sell fellow Republicans on the debt ceiling and budget deal he negotiated with President Joe Biden and win approval in time to avert a potentially disastrous U.S. default.

Leaders of the hard-right House Freedom Caucus lambasted the compromise as falling well short of the spending cuts they demand, and they vowed to try to halt passage by Congress. A much larger conservative faction, the Republican Study Committee, declined to take a position, leaving McCarthy hunting votes.

With tough days ahead, the speaker urged skeptical GOP colleagues to “look at where the victories are.” Unhelpfully for Biden, he said of the Democrats on “Fox and Friends,” “There’s nothing in the bill for them.”

A key test was coming late Tuesday when the House Rules Committee was to consider the 99-page bill and vote on sending it to the full House for a vote expected Wednesday evening.

Quick approval by both the House and Senate would ensure government checks will continue to go out to Social Security recipients, veterans and others, and prevent financial upheaval worldwide by allowing Treasury to keep paying U.S. debts. The deal would restrict spending over the next two years, but it includes environmental policy changes and expanded work requirements for some older food aid recipients that Democrats strongly oppose.

The Republican speaker said he would be talking with lawmakers as they return to Washington from the long Memorial Day weekend ahead of crucial votes.

“This is just the first step,” McCarthy said of his agreement with Biden.

With few lawmakers expected to be fully satisfied, Biden, a Democrat, and McCarthy, a Republican, are counting on pulling majority support from the political center, a rarity in divided Washington, to prevent a federal default.

McCarthy could expect no help from the right.

“This deal fails, fails completely, and that’s why these members and others will be absolutely opposed to the deal,” Rep. Scott Perry, R-Pa., the chairman of the Freedom Caucus, said, flanked by others outside the Capitol. “We will do everything in our power to stop it.”

Ominously, the conservatives warned of potentially trying to oust McCarthy over the compromise.

“There’s going to be a reckoning,” said Rep. Chip Roy of Texas.

Liberal Democrats decried the new work requirements for older Americans, those 50-54, in the food aid program. And some Democratic lawmakers were leading an effort against a surprise provision to greenlight a controversial Mountain Valley Pipeline natural gas project through Appalachia.

Biden spent part of the Memorial Day holiday working the phones, calling lawmakers in both parties.

“I feel very good about it,” Biden told reporters Monday. “I’ve spoken to a number of the members,” he said, among them Senate Republican leader Mitch McConnell, a past partner in big bipartisan deals who largely has been sitting this one out.