Four years after Baltimore County Executive Theodore G. Venetoulis and some half-dozen other officials defeated the scandal-ridden Democratic organization here, local Democratic voters have yet to decide if they want him to win the gubernatorial nomination.

Although Venetoulis is leading in his home county in the polls, his staff and those of his three rivals say that half the Democrats in the largest county of Maryland do not know who they will support in Tuesday's primary.

It is a situation that Acting Gov. Blair Lee III, Baltimore City Council President Walter S. Orlinsky and former state secretary of transportation Harry R. Hughes hope to exploit for their candidacies. Venetoulis has been one of the county's more controversial chief executives, polarizing the citizens into strong pro-and anti-Venetoulis camps, or as a Venetoulis staffer describes them, "the Ted-lovers and the Ted-haters."

Besides, local officials say, the voters are pre-occupied with county races in what is being billed here as the first "post-machine" election and may never make up their minds on the gubernatorial contest. The gubernatorial camps say that the usual pool of volunteers has become engaged in the close local elections that there has been a shortage of workers for their campaigns. "I've been going door-to-door, canvassing my whole district and people age of workers for their campaign elections," said Del. Timothy R. Hickman, a Democrat from Cantonsville. "I think this election is the completion of the process begun in 1974, the final destruction of the machine."

Hickman, like most local candidates, has not announced an endorsement in the gubernatorial race.It might injure his chances in his tight contest for the State Senate.

When voters go to the polls in Baltimore County, which surrounds Baltimore City like a horseshoe, they will be confronted with the largest number of candidates in county history, 357 candidates running for the 83 state and county positions. Everyone points to this plethora of candidates as the greatest sign that the mahines, which once decided not only who would run but who would win, are gone.

"This is a very, very different county now," said Del. John S. Arnick, a candidate for the State Senate vacated by retiring boss Roy N. Staten, Arnick, who learned his politics and won his support in the Staten organization, is facing heavy opposition from a reform-styled candidate, Del. Patrick T. Welsh.

"Four years ago the political corruption convictions (of former county executive Dale Anderson and his political lieutenant Samuel A. Green) had a lot to do with the elections," Arnick continued. "Since Venetoulis won that way, everybody thinks they can repeat his success."

Venetoulis' upset victory in 1974 is credited here in part, with toppling a machine that had won national notoriety for its corrupt officials. It was Baltimore County, as well, that produced Spiro T. Agnew who was forced to resign as vice president after pleading no contest to one count of tax evasion.

Since the county accounts for 20 percent of the Democratic votes normally cast in state primaries, all camps are looking here for a decisive vote in this-close race.

The Venetoulis camp, which earlier this summer had no greater hopes than to break even in Baltimore County, is noe predicting that Venetoulis will carry the county with some 50,000 of the 110,000 votes predicted to be cast.

"We've been compling our canvass reports and they're coming in 50 to 55 percent in favor of Venetoulis," said Diana Vincent, coordinator of the Venetoulis headquarters in the county. "Lee and Hughes are running second and third."

While his supporters make such claims with a sense of pride, Venetoulis' rivals wonder how he can be satisfied with such a narrow victory in his home county. "He overpromised in his own county and I think we'll reap the benefits," said Joe Coale, campaign manager for Hughes. "Our strength is in the eastern end of the county - Dundalk, Essex, the industrial areas."

But Orlinsky and Lee headquarters said they expected to carry these same blue-collar areas - pinpointing them as their key areas of strength - a sign of the confusion reigning in Baltimore County.

"I don't see how Hughes could make such a claim," said Drew Cobb, manager of Lee's efforts in the county."

Orlinsky's camp was equally adamant. "Wally is their type of candidate," said Betty Deacon, Orlinsky campaign coordinator. "He'll surprise them all."