State Sen. Charles W. Gilchrist was strolling from car to car in the morning rush-hour traffic at a busy Gaithersburg intersection, carrying his 18-month quest for the Democratic nomination for Montgomery County executive to drivers stopped in left-turn lanes.

"Hi, I'm Charlie Gilchrist," he said, following an aide who introduced him. The 6-foot-3 Gilchrist offered his hand and flashed the broad grin that has led friend and foe alike to refer to him as "Good Ole Charlie."

Yet never once did Gilchrist ask for a vote as he shook 250 hands and handed out as many brochures. Even though he was entering the final three weeks of a three-way race that by his polls appears so close that only the "undecideds" are in the majority, Gilchrist said such a gesture would be "too pushy."

It is this understated style - combining a reluctance to come on too strong, a desire to listen to all sides and a painstaking effort to explain what he believes is right - that has most distinguished Gilchrist from his Democratic opponents in the country executive race Planning Board Chairman Royce Hanson and County Council member John Menke.

Gilchrist's supporters cite this self-effacing manner as his greatest strength in a country whose voters for decades have been intolerant of strong-arm politicians. Ironically, his opponents say that this same style is Gilchrist's most obvious weakness.

The distinctions of image tend to be the key difference between the Democratic executive candidates this year since all three are viewed by party activists as progressives in close agreement on such central issues as government spending.

Gilchrist's supporters, who have observed him as a tax lawyer and a one-term state senator from Rockville, find him "judicious," "good-tempered" - a man who had made almost no enemies.

"He's a comfortable old shoe," said Judie Mopsik, a strong Gilchrist backer.

Former congressional candidate Lanny Davis said he has written 3,000 of the supporters of his unsuccessful 1976 race to urge them to support Gilchrist. "He is terribly endearing," said Davis.

But what Gilchrist's backers call his "fair-mindness" his opponents criticize as "indecisiveness." One Democratic county leader has been heard to say publicly: "The only trouble with Charlie is that he cannot make up his mind to make up his mind."

"Yes, he listens," said one opponent who asked not to be named. "He listen to anyone who walks into the void . . . He's paralyezd for fear that he'll do something wrong."

In part because he himself was grappling with his image and in part because some of his supporters expressed concern that the was "too nice," Gilchrist was urged by some supporters to take some decisive stands recently.

Apparently following this advice, Gilchrist two weeks ago blamed the controversial police chief, Robert J. diGrazia, as a cause of "disturbing morale" problems in the police force. But Gilchrist refused to say whether he would fire diGrazia if elected.

Gilchrist's opponents immediately denounced him for making the recurring dissuasion among police officers a "political football."

However, many of his once lukewarm supporters felt that the diGrazia statement was an example that he "could stand up for the tough ones," as one of them explained. They felt the same way about Gilchrist's floor leadership during the last winter's legislative session of the hotly-fought - and eventually defeated - state pension reform bill.

"Everybody thought I was 'good ole Charlie,'" - said an annoyed Gilchrist after the dust raised by his diGrazia remarks had settled. "Now I'm a "bull in a china shop." They'll have to make up their minds."

The 40-year-old Gilchrist has not solved this riddle himself. When asked how he would describe his image, he replied haltingly, pausing for a word of reassurance along the way.

"I think people are much more varied than any one characterization don't you?" he said. "It gets on your nerves when you just hear one thing. I don't have a conscious image-making plan. I haven't tried to be tough, particularly. I'd like to think of myself as a good listener . . . I really don't think you can predict what I would do. But I think it's wrong to say I don't take positions."

This attitude has drawn to Gilchrist an energetic volunteer force that subscribes to its candidate's slogan: "We don't need a county executive who wants to run us. We need a county executive who wants to lead us."

"People in Montgomery County want someone who can evaluate all sides," said Joe O'Connell, a 30-year veteran of the county's Democratic Party. "There are lots of shades of opinion in this county. Royce Hanson is not a person who will accept criticism . . . He formulates an opinion and no one can change him."

Davis said the only problem with this style is that because Gilchrist "leaves a warmth, not a fire . . . he could become a lot of people's second choice."