A 43-member House-Senate conference committee began the search for agreement on an energy bill yesterday as President Carter held meetings with individual members of Congress to drum up support.

Twenty-five House members and the entire 18-member Senate Energy Committee sat at tables shaped in a hollow square in the Senate Caucus Room and pledged good-faith efforts to compromise their wide differences over the non-tax parts of Carter's energy plan. The even more difficult questions of taxes will be taken up later.

Carter met Monday evening with Sen. Russell B. Long (D-La.). chairman of the Senate Finance Committee who will be key player in the attempt to revive some of Carter's energy recommendations which the Finance Committee rejected.

Long is expected to try to save Carter's proposed crude oil tax, which the administration calls the centerpiece of its energy conservation program and give part of the revenue to the oil industry. Carter proposed that the revenue be rebated to the public.

The President told congressional Democratic leaders at breakfast yesterday that he and Long seemed not too far apart.

Carter met yesterday morning with Rep. Thomas L. Ashley (D-Ohio), who was chairman of the House ad hoc committee that packaged the omnibus energy bill, and send him off to do battle at the conference. Ashley promised Carter a bill "you can take some pride in."

Yesterday afternoon, Carter also met with Sens. Abraham A. Ribicoff (D-Conn.) and Lloyd Bentsen (D-Tex), both members of the Finance Committee.

Ribicoff, one of Carter's few supporters on the committee, almost certainly will be a conferee on the energy tax provisions. Bentsen is a leading advocate of lifting price controls from newly discovered natural gas, which will be one of the toughest issues in conference.

The House approved Carter's plan to continue controls at higher levels while the Senate voted 50 to 46 for deregulation.

Deputy White House press secretary Rex Granum said the President was not talking compromise with Bentsen. But when the issue was up in the Senate, the administration reportedly was willing to raise the gas price ceiling higher than the President orginally proposed in exchange for continued regulation.

The Senate Finance Committee rejected, and the Senate is expected to follow suit, all three of the main taxes Carter proposed. The House approved all three, and the conferees will bump heads on each.

While Carter calls the crude oil tax the centerpiece, his less publicized proposed tax on industrial use of oil and natural gas would account for more than half the oil savings in his entire program. The third tax is on the purchase of low-mileage cars.

The two chambers are nearly as far apart on most non-tax portions of the bill. The House largely approved Carter's program. In addition to its differences with the Senate on natural gas, the House voted to require rate structures to save energy, while the Senate refused to move into this area of traditionally state regulation.

The House voted strong measures to push industry and utilities from use of oil and natural gas to more abundant coal. The Senate bill was considerably weaker.

The conferees began work yesterday on what appears to be the easiest section of the bill to compromise on. This is a program requiring local utilities to advise customers of the advantages of insulating their homes and to offer to make inspections. The House bill generally permitted utilities to go further and make loans and install insulation for their customers. The Senate bill generally forbade it.

The conferees discussed this point off and on for two hours yesterday afternoon and broke up for the night without agreement.