Faster than you could say "House Rule XLVII," the House yesterday granted its members the right to earn an extra $7,510 a year in outside income from speaking appearances, pulling House members even with their Senate colleagues in the honoraria sweepstakes.

The rules change also may have lifted all House limits on other types of outside earned income such as professional fees, although that point was subject to differing interpretations as lawmakers scrambled after the fact to determine exactly what had been done.

The deed was accomplished with stunning swiftness -- and the apparent, although silent, approval of the Democratic and Republican leaderships -- by Rep. John P. Murtha (D-Pa.). One of the House's least publicly visible but most adept string-pullers, Murtha is known for his willingness to take on such politically risky chores for his colleagues.

With House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) presiding and only a handful of lawmakers on the floor, Murtha gained unanimous consent for a resolution striking down a section of Rule XLVII that limited House members' outside earned income to an amount equal to 30 percent of their government salaries.

The Murtha resolution replaced this section of the House rules with new language saying the only limit on outside earned income was that set in law.

The immediate effect of this change was to lift the 30 percent limit, set in the now defunct section of the House rules, to 40 percent, the limit set when Congress enacted an omnibus spending measure last December. With passage of that law, the limit on outside income from speeches was raised from 30 percent to 40 percent for all members of Congress. But the new ceiling effectively applied only to senators, because Senate rules set no limits on honoraria income, while the House rule setting the 30 percent limit remained, until yesterday, the governing edict for members of that chamber.

From now on, House members will be allowed to earn and keep up to $30,040 in honoraria from speaking engagements this year -- an amount equal to 40 percent of their $75,100 annual salaries. The old limit was $22,530.

The resolution, because it applies to House rules, took immediate effect and does not require action by the Senate or President Reagan.

What was not immediately clear was whether this rules change would also effectively lift all limits on other types of outside earned income, such as legal and professional fees. This appeared to be a possibility, however, because while the 30 percent limit set in Rule XLVII applied to all outside earned income, the 40 percent limit established in law applies only to honoraria.

Fred Wertheimer, president of Common Cause, the self-described "citizens lobby," charged that House members could now enjoy "unlimited earnings from law practices, corporate relations, commissions" and other outside activities.

"This is an open invitation to ethical abuses," Wertheimer said. "It's a rape of the process by Murtha and others . . . . If this is not corrected immediately, no member of the House will be in a position to complain about what [former White House aide and now lobbyist] Mike Deaver has been up to."

The House adopted the Murtha resolution as its fourth item of business yesterday, immediately after the opening prayer, the routine approval of the journal from Monday's session and a one-minute speech about the visiting chaplain.

Under House rules, the action could have been stopped by the objection of any House member. House Minority Whip Trent Lott (R-Miss.) was on the floor at the time but did not object.

Rep. John Patrick Hiler (R-Ind.) rose to question the resolution, but dropped any objections when assured by Murtha that it had been cleared by GOP leaders.

"The implication was that it was cleared by the party leadership," Hiler said later. "I presume that Mr. Murtha would not lie on the floor. On that basis I did not object."

Later, Rep. Robert S. Walter (R-Pa.), who was not on the floor during the rules change but who is known for raising a constant stream of objections to actions by the Democratic majority, said, "Somewhere, a deal was cut."

Neither Murtha nor Lott could be reached for comment after the House action, which took about two minutes. Michael S. Johnson, executive assistant to House Minority Leader Robert H. Michel (R-Ill.), said "no" when asked if the resolution was cleared in advance by Michel.

"I don't know anything about it," said Christopher J. Matthews, press secretary to O'Neill.

The biggest potential winners from an increase in the honoraria limit include O'Neill, whose salary is $97,900, and Michel and Majority Leader James C. Wright Jr. (D-Tex.), who are paid $85,000 a year.

Other main beneficiaries will be chairmen and senior members of key committees who routinely have exceeded the 30 percent limit and under House rules must contribute the excess earnings to charity. In 1984, according to Common Cause figures, Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) received $93,000 in honoraria and contributed $72,000 to charity.