INDIANAPOLIS -- Mario Cuomo, who has made a specialty of being the man who isn't there, nonetheless has a message for his Democratic Party. It is that passion counts.

The New York governor delivered -- and embodied -- the message here the other night to a rapt, record crowd of party faithful in a state where Democratic victories are as rare as people bored by basketball. Without even trying, Cuomo made six announced Democratic presidential candidates and Republican front-runners George Bush and Bob Dole, who also spoke in Indianapolis this week, appear to be sticks-in-the-mud.

The circumstances of the Cuomo speech were typically bizarre. The stay-at-home governor's midwestern itinerary was marked by the sort of mishaps that seem to afflict only him. He was to have come west on Sunday morning to join his fellow governors at their annual meeting in Traverse City, Mich., but a warning light on his small plane forced the shutdown of an engine and an emergency landing back at Albany. Cuomo declined the offer of a slower backup plane and went home.

The result was that when two key New York legislators, Sen. Daniel P. Moynihan and Rep. Thomas J. Downey, met with the nation's governors Sunday afternoon on their bills to reform welfare -- an issue of vital concern to New York and to Cuomo -- the governor of New York was one of the few not at the table. Nor did he appear later in the meeting, which concluded on Tuesday.

Cuomo's second engagement was with the National Conference of State Legislatures. He was to speak at their luncheon here on Tuesday, but yielded that time to Vice President George Bush when Bush informed NCSL that would best suit his schedule. Cuomo did fly in to speak to the Indiana Democratic Party Jefferson-Jackson dinner Tuesday night -- an event that originally had been just an add-on to his schedule.

There, Cuomo was a smash. He drew 1,900 people, including some out-of-state legislators who had hoped to hear him at their own event. For Indiana Democrats, this was the biggest party fund-raiser in the two dec- since they last won the govern- and party chairman John Livengood was ecstatic.

Hoosier Republicans, who control the state government and both Senate seats, fear a bruising 1988 gubernatorial primary between Indianapolis Mayor William Hudnut III and Lt. Gov. John Mutz, the choice of retiring Gov. Robert Orr. And Democrats finally have a rising star in their potential gubernatorial candidate, Secretary of State Evan Bayh, the 32-year-old son of former senator Birch Bayh.

To this crowd of eager partisans, Cuomo delivered a message both inspirational and intimidating. After seven years of Ronald Reagan's rhetoric, he said, ''the American people have had their fill of charisma . . . {and} will insist on competence. And it is already clear that our candidates will meet that test easily.'' But he had no sooner voiced that comforting thought than he added, ''That will not be enough. Nor should it be.'' He discerned a ''yearning for inspiration'' that he said had led the American people to elevate Oliver North, the ousted Reagan National Security Council aide, to undeserved hero status during his appearance before the Iran-contra hearings.

''So badly did we want a true believer, a hero,'' Cuomo said, ''many of us were fooled into overlooking the fact that the men we chose to hoist onto our shoulders were in the proc- of destroying one of our most important values . . . the rule of law.''

But even as they reject North's example, Cuomo said, Democrats cannot ignore the public demand for ''intense and daring commitment.'' Nor can they afford to forget Yeats' warning of a time when ''the best lack all conviction, while the worst are full of passionate intensity.''

Twice more in the speech, he said Democrats must demonstrate that ''passionate intensity'' if they are to win in 1988. Cuomo is far too clever not to know that he left many in his audience thinking that he displayed far more of that quality than any of the announced candidates in their party. In conversations the next two days, the question repeatedly asked was: Could Cuomo be plotting to become a late entrant in the Democratic race?

The answer is almost surely no. For some reason or reasons, buried in his complex mind and personality, Cuomo seems willing to accept the speech accolades but yield the White House campaign to others, as readily as he accepted the cancellation of his flight to Traverse City.

Mario Cuomo, the man who isn't there, materializes just often enough to remind the Democrats what they are missing.