The House yesterday overwhelmingly rejected an effort to bar production of neutron weapons after an unusual and often emotional five-hour debate that ran over two days.

By a 297-to-109 vote, the members defeated an amendment by Rep. Ted Weiss (D-N.Y.) that would have eliminated all funds for neutron weapons from the fiscal 1978 Energy Research and Development Administration authorization bill.

That measure authorizes a classified amount of money for initial production of neutron versions of the 8-inch artillery shell and 56-mile-range Lance Missile warhead.

If produced, they would be the first tactical nuclear weapons designed primarily to kill enemy personnel by radiation rather than destroying their tanks and installation through blast and heat.

The advantage of neutron weapons, according to proponents, is that by enhancing radiation and cutting down on blast and heat they cause less collateral damage in civilian population areas adjacent to the battlefield.

Yesterday's House action clears away the final congressional obstacle before President Carter makes his own decision on whether to produce the weapons. Both houses of Congress have now authorized and appropriated funds for the new neutron warheads.

Should Carter decide to go ahead with production, Congress, under legislation passed in July, and would have 45 days to pass a joint resolution overruling that decision.

Carter's production decision had originally been expected in August. It has been delayed awaiting a guarantee of public support from hesitant NATO countries on whose territory the weapons would be deployed and possibly used.

After yesterday's vote Weiss said, "This was only the first round. There will be a second round (under the 45-day provision) if Carter proceeds with production."

A veteran Armed Services Committee aide said yesterday the debate on the Weiss amendment was the longest he could recall on a single provision in a military authorization bill. Since speakers were mostly limited to five minutes, dozens of members participated in the sometimes heated exchanges.

Yesterday's key defender of the neutron weapons was Rep. Thomas J. Downey (D-N.Y.), the youngest member of the armed services panel and usually a critic of Pentagon pograms.

Downey said, "Few issues have given me more trouble than this one." He said his decision to support neutron production stemmed from a belief that "in the framework of gamesmanship . . . where both [the Soviets and the United States] add to their arsenals . . . we must respond to maintain our position" in the eyes of the NATO ad Warsaw Pact nations.

"The international advantage of the neutron bomb," Downey said, "is just another stpe to show to the Russians we mean business [in Europe].

Rep. Ronald V. Dellums (D-Calif.) voiced his strong moral opposition to the neutron weapons on the grounds that they make nuclear war "thinkable . . . and ultimately inevitable." He also challenged Downey's argument, saying the weapons complicate current attempts to get conventional and nuclear force reductions in Europe.

Rep. Barbara A. Mikulski (D-Md.), another opponent, read off a vivid description of the effect radiation would have on individuals.

She was followed by Rep. John F. Seiberling (D-Ohio), who said, "This is what the German people have been hearing. We will save them by destroying them."

Rep. Robert L. Leggett (D-Calif.), in making a strong defense of going ahead with neutron production, said the weapons are "not as lethal and diabolical as some may think."

He charged but "scare headlines about a killer warhead" (which appeared in The Washington Post), had "set the parameters of the debate." He called the decision to put neutron warheads "on the last 300 Lance launchers . . . much ado about not much."