The "serious problems" facing the Democratic Party are rooted not in its ideology but in its inability to work as a unified "delivery system" of money and organizational structure on behalf of Democratic candidates, according to AFL-CIO President Lane Kirkland.

The Democrats also have become "riddled with factions" that should be paying their way in fund-raising for the party, he said.

Kirkland, in a wide-ranging interview, added that the Democrats must reduce the number of presidential primaries if they are to defeat the richer, better-organized Republican Party.

The occasion was the start of a 50-city tour that Kirkland and his top lieutenant, Thomas R. Donahue, are planning to take over the next six months. They hope to reach grass-roots labor union members and discuss ways to reinvigorate the labor movement and increase its political clout.

In discussing the Democrats' overwhelming defeat in last year's presidential election, Kirkland disputed the notion that the party had lost touch with the mass of voters and must move toward the ideological center.

"The Democratic Party," he said, "has serious problems. It is not the problem of the kind that has been most fashionably bruited about: ideas, message and so forth. But it is its capacity to function as a delivery system.

"I traveled through a good bit of the country, and I would have been hard put to find a place where there was any visible delivery system or infrastructure that I would describe as an adequate political party . . . . Local and state people didn't get the money that had been promised to them.

"The proliferation of primaries has been harmful and created an extraordinary ordeal for candidates . . . because it consumes a very large amount of money, energy and time . . . . Reducing the number of primaries would reduce the wear and tear on candidates and the drain on resources."

Democratic presidential primaries grew from 17 in 1968 to 31 in 1980 as one of several changes aimed at broadening grass-roots support and diminishing the role of party regulars. But a package of 1982 party rule changes has begun shifting the emphasis, reducing primaries to 26 in 1984 and giving party officials more delegate slots at national conventions.

Kirkland said the trend must be accelerated if Democrats are to regain the White House. In addition, he said, the party should "move a bit back" to the pre-1968 system in which conventions had real power and were "more than a bit of window-dressing and show biz."

Kirkland also said chances are "very good" that the 13 million-member labor federation will again seriously consider an early endorsement of a presidential candidate, despite the widespread contention that labor's early support damaged the candidacy of Walter F. Mondale by labeling him a tool of unions' "special interest."

Kirkland complained that while organized labor in recent decades has been a dominant funding source for Democratic candidates and for the Democratic National Committee, the party has become "riddled with factions who . . . drain the resources but who don't put resources in."

Asked to identify those factions, Kirkland said, "All of them -- except us."

In particular, he said he was referring to the seven official Democratic caucuses within the DNC: black, Hispanic, women's, lesbian-gay, Asian Pacific, business and professional, and liberal-progressive. While the caucuses do not have budgets or staff assigned to them, Kirkland said they demand and receive DNC staff attention without supporting the party financially.

Kirkland said he has met with new Democratic National Chairman Paul G. Kirk Jr. but has not formally discussed his ideas about changing party rules.