As the crowd bellowed his name last week, a shirt-sleeved Walter Mondale told one of the largest political rallies ever to gather in the city's Market Square that the upcoming election campaign was about them, hard-working people who have faced tough times under the Reagan administration.

But just off the square, behind the stenciled sign in the window of Benny's New Diamond Cafe welcoming the Democratic presidential candidate, the lunch-hour crowd of carpenters, bricklayers and printers did not necessarily share Mondale's view of the Reagan administration.

Benny's is located in one of the economically hardest hit cities in one of the hardest hit states in the country, and it would seem the perfect place to find the long-suffering blue-collar workers whom Mondale has tried to reach with his economic policies.

"Ronald Reagan is for cutting big business a tax break so big business can afford to invest in new projects and get jobs for young kids," said Michael Mountain, a 24-year-old unemployed brick and block laborer. "Putting Mondale in there, you're putting a young person back on the welfare rolls," Mountain said. "Look at all the new buildings put up during Ronald Reagan's administration. When I think of Walter Mondale, I think of Jimmy Carter and all those promises he didn't keep."

Tom Burns, another construction worker, said, "I think the country's in better shape than four years ago. There's plenty of room for improvement. But overall, I think Americans feel better about America."

For Mondale's senior advisers, the Tom Burnses of the world present one of the toughest problems they face in the election campaign: how to shift the focus of the campaign from the economic prosperity many Americans enjoy today to the problems they believe may lay ahead. That dilemma is coupled with the continued association of Mondale's economic proposals among some voters with the high interest rates and inflation under President Carter, the man under whom he served as vice president.

Senior Mondale advisers said their strategy is to point to the future, stressing the budget deficit, the trade deficit and the unbalanced nature of the economic recovery under the Reagan administration and how these problems could harm future generations.

The advisers said they hope that, as a result of the exposure of Mondale's economic proposals during the first presidential debate last Sunday, voters will see that their candidate has a concrete plan for the economy's future and that President Reagan prefers to wish potential problems away.

At campaign stops last week, Mondale spoke to large, enthusiastic crowds, which booed the "unfairness" of Reagan's tax breaks for the rich and cheered Mondale's espousal of more jobs and fairer tax treatment for the little guy.

"On Sunday night in Louisville, the campaign in '84 began because people for the first time heard Ronald Reagan and Walter Mondale talk about the economy and the two plans for America," said William A. Galston, a top issues adviser for Mondale. "The future of the economy is important. This debate about the future is just now being joined. There's a new focus on the issues . . . Walter Mondale will tell the truth about the economy's future and trust in the judgment of the American people."

But telling what Mondale sees as the truth may be hurting his campaign. One of the first campaign issues was Mondale's proposal to raise taxes to close the federal budget deficit. Mondale pledged to cut the "Reagan deficit" by two-thirds by the end of the decade by reducing defense expenditures (but also restoring cuts made by Reagan in social programs), reducing the interest payments on the federal debt and increasing taxes.

The Reagan-Bush campaign, in a series of television commercials, has harped on the tax issue and the President last week told audiences to expect hefty tax increases if Mondale is elected.

However, many Mondale supporters interviewed at random last week said they wouldn't mind paying higher taxes so long as the tax money went to a worthy cause and the wealthy also paid their fair share of taxes. They seemed to agree with Mondale that the wealthy do not pay their fair share of taxes now.

A Washington Post-ABC News poll of 11,807 registered voters taken just before the debate showed just how far Mondale will have to come on economic issues. When asked under which candidate they personally would be better off, 54 percent of voters polled chose Reagan and 34 percent selected Mondale.

Voters also said they would trust the handling of the nation's economy to Reagan rather than Mondale by a margin of 58 percent to 34 percent.

When asked which presidential contender can better cope with the federal budget deficits, voters gave Reagan a 49 percent approval rating to 38 percent for Mondale. Polls also consistently have blamed the Democrats and previous administrations for the deficits, not President Reagan.

William C. Price, executive vice president of the Greater Cincinnati Chamber of Commerce, was not unique among voters when he said last week that he plans to vote for Reagan even though he didn't believe the president's assertion that budget deficits don't help lead to higher interest rates and even though he said he was disheartened by the president's performance during the debate.

"I think it goes back to the good times," Price said. "Things are getting a lot better."

Under Mondale's proposal, growth in the Defense Department budget would be reduced and some domestic programs would be cut, but many programs reduced under the Reagan administration would be restored.

Families earning $25,000 or less would receive the benefits of tax indexing, but those earning more would have their taxes indexed only if inflation exceeded 4 percent.

The third phase of the Reagan tax cut would be limited for married couples earning more than $60,000 annually and single persons with incomes exceeding $45,000. Mondale also would add a 10 percent tax surcharge for married couples with incomes exceeding $100,000 and single persons with incomes of more than $70,000.

In addition, Mondale would limit tax shelters and loopholes and place a 15 percent minimum tax on corporations.

The additional tax revenues generated by these steps would be placed in a special fund only to reduce the deficit, Mondale said. Impartial tax analysts said Mondale's proposal would not spare many middle-income taxpayers.

However, in interviews during campaign rallies in five industrial cities in the Northeast and Midwest, Mondale supporters said they wouldn't mind paying higher taxes if they felt the revenue would be spent on projects to help the poor.

"Someone has to pay for programs," said John Soloman, a nattily dressed computer software salesman in Pittsburgh. "I don't mind putting in my fair share. Too many rich people get tax loopholes I can't take advantage of. People might not want him raising taxes, but at least they know what he's going to do."

"Times are good right now," said Gail Hearn, a biology professor at Beaver College outside of Philadelphia. "It's hard to convince people bad times are ahead." Would she be willing to pay higher taxes? "Sure, particularly those of us who are working steadily, we can afford to pay a little more."

"It depends on how much of an increase it is," said Lotti Caudle, a Detroit secretary. "A tax increase is very minimal compared to what Reagan has given us."

A senior Mondale adviser acknowledged that all of Mondale's economic proposals will not appeal to all voters. The record U.S. trade deficit will get farmers excited, and talk about interest rates will attract the attention of businessmen, the adviser said. Talk about increasing taxes, on the other hand, probably will turn off high-income voters, the adviser said. "All of the information available to us suggests the American people overwhelmingly believe Walter Mondale is speaking the truth, that taxes must go up in 1985," Galston said. How strong the candidate's emphasis on taxes will be "will depend on events. There is an issue of tax fairness in this country, and Walter Mondale has said many times that he doesn't intend to ask average Americans to pay more so millionaires can pay less. He has put forward a tax plan which is very, very specific about who will pay what when."

At every campaign stop last week, Mondale stressed the problems of the economy and the assertion that the president has said little about what he plans to do about the deficit and high interest rates. "The question isn't whether Ronald Reagan will raise taxes, he is," Mondale shouted to a South Philadelphia crowd. "Middle- and moderate-income taxpayers have paid enough."

In Pittsburgh, Bob Macy, a 36-year-old unemployed steel worker, took center stage before Mondale took over the rally. "We're here because I lost my job at the Duquesne Works, U.S. Steel Corp.," Macy said. "Our reward was the shutdown of this facility . . . and our jobs exported to Korea and Brazil." The crowd booed.

"This campaign is about Bob Macy and the Bob Macys of this country, caring family people who've had the bottom drop out from under them," Mondale said.

But in Benny's cafe, that was not enough to arouse much enthusiasm. "I'm going to vote for Mondale just because I don't like Reagan," said Bob Beres, a mail handler at a local newspaper. "He's the lesser of two evils."