The Pentagon has asked Congress to defer $43 million it had sought for production of the controversial Bigeye binary chemical bomb because it has discovered that the bomb could explode on its own and spew deadly nerve gas while being carried by an American aircraft.

"The problem was discovered late last year," Dr. Ted Gold, deputy for chemical matters in the office of the assistant to the secretary of defense, said yesterday. "But we believe a solution is in hand."

The problems of the Bigeye will provide new legislative ammunition for opponents of the Reagan administration's $2 billion, five-year program of binary chemical weapons development, according to sources on Capitol Hill.

The House Armed Services Committee removed the Bigeye money from the fiscal 1984 defense authorization bill last week, sources said. But production money for 155mm binary chemical artillery shells was left in.

Binary weapons are supposed to be safer than present chemical weapons because they consist of two separate cans of chemicals that don't become lethal until they are mixed.

To arm a Bigeye bomb, the aircraft pilot "activates the weapon and it proceeds through an automatic mixing sequence" that in 10 to 15 seconds generates VX, a persistent nerve gas, according to a recently released General Accounting Office study of chemical weapons.

When the pilot releases the armed chemical bomb from underneath his plane, according to the GAO report, a fuse explodes a charge that puts holes in the nose of the weapon. As the bomb falls, 191 pounds of the now-liquid agent spray out within two seconds, "creating droplets that fall to the target area," the report said.

On the ground, the liquid sticks to leaves, grass and other matter. Colorless and odorless, it remains deadly for one to three weeks and can kill a person if it touches bare skin, according to congressional testimony last year.

In a Pentagon review of the Bigeye program last year, it was discovered that there was a "pressure buildup" inside the bomb if it was mixed but not dropped within an hour, according to Gold. During that time, the chemicals that mix to create the VX continue to react to each other, resulting in gaseous byproducts, particularly under certain high temperatures, sources said.

Gold said he was "reluctant" to delay the Bigeye program for a year because the bomb is "our most pressing need" to deter Soviet use of chemical weapons. Without the Bigeye, he said, the arsenal of older, already-mixed, "unitary" weapons does not contain a persistent, or long-lasting, bomb that for delivery behind enemy lines.

One solution being studied, according to sources, is to delay the mixing process until the Bigeye has been dropped from the airplane.

The Air Force had planned to build 444 Bigeye bombs in fiscal 1984 and 4,066 in fiscal 1985. Overall, the Air Force planned to spend $800 million on Bigeye bombs, according to Senate testimony last year. The Navy, which is managing the Bigeye development program, also planned to produce Bigeye bombs in fiscal 1984 and 1985.

The only chemical bomb in the current arsenal is the Weteye, which contains GB, a nerve agent that loses its deadly effects within hours.

Congressional opponents of the binary chemical weapons program last year cut production funds for both the Bigeye and the 155mm shell out of the fiscal 1983 budget.

In releasing the GAO report Thursday, Rep. Clement J. Zablocki (D-Wis.), chairman of the House Foreign Affairs Committee and a leading opponent of the new chemical weapons, said it "underscores the importance of our "pursuing a chemical weapons arms control agreement rather than initiating a chemical arms race."