WILL THE HOUSE of Representatives, when it returns to town later this month, do anything about Rep. James Weaver (D-Ore.)? It should. Mr. Weaver has long been known as one of the House's most eccentric members. Now questions have been raised about whether he may have violated an important House rule and may have misused confidential government information.

The problem stems from the risky business of commodity trading. Mr. Weaver was a professional commodities trader with a seat on the Pacific Commodities Exchange before he was elected to Congress in 1974, and by 1978, according to Wall Street Journal reporter Brooks Jackson's examination of Mr. Weaver's disclosure records, he began trading again -- in Treasury bill futures, bond futures, silver futures, cattle futures. As is common in commodities markets, he did some of his speculating on margin, putting up only 10 percent of the purchase price in cash. As is also common in commodity markets, he lost a lot of money.

So he began borrowing from his campaign fund -- loans that reached a total of some $81,000 by the summer of 1984. He says he signed an interest-bearing note and has paid the interest, but admits that as of last month he had not repaid any principal. Any profits from commodities trading, he adds optimistically, would have gone to pay off the loan. And if he had made a killing, he wouldn't have had to bother to raise campaign funds; he could have financed his own campaign.

This bizarre conduct raises two questions the House, through its ethics committee, should answer. The first is whether Mr. Weaver broke the rules by borrowing campaign funds to pay off personal debts. Signing a note may not make the use of campaign money legal if the note is not repaid. (Whether the loan should have been reported as personal income can be left to the IRS.) The critical thing is that campaign contributions aren't supposed to go to the personal benefit of candidates.

The second question is whether Mr. Weaver made use of the confidential government information he, as a member of certain committees, had access to. He says he did not, and the fact that he lost money tends to support his denial. But the House, through its ethics committee, should check the facts itself. Mr. Weaver has been entrusted with important responsibilities by the House generally and the Democratic caucus in particular. They have a duty to see that there is a thorough investigation and an appropriate penalty if he has betrayed his trust.