When Abe Lincoln ran for Congress in 1846, his sole campaign expense was said to be 75 cents for a barrel of cider to reward supporters.

Nowadays, the Federal Election Commission has more money to keep track of: $239 million was spent in the 1980 congressional races and more than $191 million in the presidential campaign that year.

To do that task, the FEC inspects the campaign contribution reports of candidates for federal office, administers the public financing of presidential campaigns, monitors political action committees and investigates complaints of improper campaign financing. Some officeholders say the agency goes too far with onerous requirements. Others object that in its efforts to be fair, the FEC does not do enough.

Karen Marchioro, chairman of the Washington State Democratic Party, is one who thinks the agency does not do its job. In 1980, Marchioro complained about the way Republican Slade Gorton had financed his race for the U.S. Senate. Gorton had borrowed $200,000 from his father, and the Democrats protested that no one, not even a family member, can contribute or loan more than $1,000 to a candidate.

Gorton, who was then Washington State's attorney general, responded that the money was part of an inheritance that he could claim at any time. But this spring, more than 14 months after the complaint was filed, the FEC decided the contribution violated the law, and his campaign committee agreed to pay a $5,000 penalty.

What particularly galled Marchioro was that the decision was made public in a statement from the office of now-Sen. Slade Gorton. In a press release, headlined "FEC Dismisses Gorton Campaign Complaint," Gorton said the FEC had found a "technical error" that obliged it to impose a penalty.

The complaint against Gorton illustrates the major problems the FEC faces. Disputes may take months or even years to resolve. The agency sometimes is accused of being too secretive. And it must investigate complaints against the very people who approve its budget.

The FEC is not known for its haste. A spokesman recently noted with pride that the agency had completed audits of the 1980 presidential campaign early this year. That is better than the audits of the 1976 campaign, which took four years to complete. Of the 100 to 200 complaints filed each year, some stretch on for years. If a complaint is filed against a congressional candidate in this year's election, it is conceivable the candidate could be elected and serve a two-year-term before the matter is resolved.

Frank P. Reiche, the former tax lawyer who now chairs the six-member commission, said the time required to settle complaints is dropping. The delays, he said, are necessary to give each side time to make its case, to allow the commissioners to examine the evidence, to investigate the complaint further, to let the commissioners make a final decision and to negotiate a penalty. Normally, the FEC reaches agreement on a penalty rather than going to court.

Secrecy also is necessary for fairness, Reiche said. "If you're talking about a complaint made in the latter stages of a campaign, the impact could be devastating."

The FEC does not publicize results of a complaint but makes its file available to anyone who visits its offices on K Street NW. Reiche said that if the agency publicized results, it would have to make a political decision of when to issue a press release and that could damage the FEC's credibility.

Investigating complaints about members of Congress has not always endeared the agency to those who control its purse strings.

Sen. Roger W. Jepsen (R-Iowa) and several other senators, for instance, have urged that the agency be abolished. The FEC investigated, and later dismissed, a complaint that in the 1978 election, Jepsen's wife contributed more than $1,000 to his campaign.

"[Walking on] eggshells is a 25-hour-a-day activity around here," Reiche said. "It's sort of the nature of the beast. We are to some extent controlled by the people we regulate."

Fred S. Eiland, an FEC spokesman, dismissed complaints that FEC penalties amount to a slap on the wrist. He noted that a few years ago the agency assessed a $75,000 penalty against the National Education Association and a $25,000 penalty against the Citizens Committee for the Right to Keep and Bear Arms. The largest penalty assessed against an individual was an $18,000 fine for an Alabama businessman who secretly contributed far more than he was allowed in 1978 elections.

And all 10 of the 1980 presidential candidates who received public money had to repay some of it. The repayments, which are not the same as penalties, were made after complex audits found spending errors.

Very few complaints end in penalties and most penalties are small. In fiscal 1981, only six of the 106 complaints received were found to be violations and all were settled out of court. From 1974 to 1981, the FEC assessed $413,000 in 377 cases, or about $1,100 a case.

In May, the FEC asked Congress to revise some of the laws it has to enforce. The agency asked Congress to prohibit candidates from making false statements while fund-raising.

It also asked Congress to review the $1,000 limit on what a family member can contribute to a campaign. That limit has caused problems in communal property states, where money is considered the joint property of a husband and wife. Thus a candidate can use more than $1,000 of his or her spouse's money since it belongs to both of them.

However, when a candidate in one of those states wants to take out a new mortgage on his or her home to finance a race, both spouses must sign the papers. Each is considered to have contributed half the amount of the mortgage to the campaign, violating the law if the mortgage is for more than $2,000.

So far, however, Congress has not had a chance to take up the proposals. And it probably won't find time to pass them before it recesses, to face another election.