Squabbling Republican budget negotiators yesterday fell about $2 billion short of reaching a united front on next year's deficit, even after narrowing about $10 billion worth of differences by the wave of an accountant's wand.

After a day of backroom negotiations that forced several delays in the official House-Senate conference on the fiscal 1983 budget, Republicans neared tentative agreement on major tax and spending items but were still at odds over the projected deficit.

At one point late in the day, several sources said tentative earlier decisions tallied up a deficit of almost $105 billion. House GOP conferees were insisting that they could not accept a deficit of more than $102.9 billion, arguing that anything more would jeopardize chances of passing a budget compromise in the House.

Moreover, some senators were described as restive over tentative agreements on cuts in defense and housing programs.

A brief late afternoon session of the conference ended inconclusively, leaving the Republicans the evening to try to work out their own differences.

After a two-hour evening session, the Republicans indicated they were close to an agreement, although not quite there. "We're very close in terms of what we're going to agree to," said Senate Budget Committee Chairman Pete V. Domenici (R-N.M.), confirming that the deficit gap had been narrowed but declining to discuss details.

In their earlier talks, the Senate Republicans met their House counterparts more than half-way on most big items, including a dispute over spending and revenue assumptions in which the nonpartisan Congressional Budget Office calculated that the House had underestimated its deficit by about $10 billion. While the House Republicans said their deficit was $99.3 billion, CBO said it was nearly $110 billion.

Easing the way for an agreement, Senate Republicans, who had originally based their budget on CBO's numbers, agreed to go along with the House numbers, narrowing the deficit differences between the two houses considerably.

They also agreed, at least tentatively, to accept the House plan for $20.9 billion in new taxes next year, along with $1.1 billion in new user fees. The Senate had proposed a total of $23.4 billion in additional taxes and fees.

On defense, they accepted the proposed House cut of $7.8 billion from the administration's buildup program. They added back $1.1 billion to the House proposal for food stamps and restored some funds for Medicaid, but generally went along with the deeper House cuts for most domestic programs.

On the controversial issue of cost-of-living increases, they agreed to a 4 percent limit for federal pay and pensions over the next three years. Social Security, railroad pensions and service-connected veterans benefits were exempted from the "cap." The Senate had wanted a freeze next year on federal pay and pensions and veterans' benefits.

"The Senate has given in considerably to accommodate the House," said House Minority Leader Robert H. Michel (R-Ill.) at one point in the negotiations, suggesting that the Senate conferees, rather than splitting the difference, had generally given the House three-quarters of what it wanted.

But Michel and other House members continued to insist that a deficit of more than $104 billion was too high. Arguing against raising taxes to make up the difference, Michel said, "It's going to be hard enough to get some members to buy it (a compromise) because of the deficit," even if the deficit is less than $103 billion.

Even after the Republicans come to an agreement, it must still be accepted by House Democrats, who control the House conferees group. The Democrats remained noncommittal but said they were not interested in obstructing the conference.

After a conference agreement is reached, it must be voted on by both houses. Some budget leaders in both houses are nervous that any major changes in the original plans approved by their houses could jeopardize final passage.