The central committee of the Virginia Democratic Party voted overwhelmingly today to hold a convention rather than a primary to nominate its 1978 candidate for the U.S. Senate seat now held by Republican Sen. William L. Scott.

The party leaders, who approved the convention by a lopsided voice vote, were obviously discouraged by the decisive defeat of Democratic gubernatorial candidate Henry E. Howell in the Nov. 8 election, and were anxious to avoid a divisive primary.

Speaker after speaker said the party could not afford to have a large field of Senate candidates raising millions of dollars to fight each other in a primary and then expect to raise enough money to wage an effective campaign against the Republican nominee.

But W. Pat Jennings, former member of Congress and now a national Democratic committeeman, told the Democrats: "I still favor a primary on principle, but I don't think we can afford to have one. I would love to be able to travel the country in a Lear jet but all I can afford is a Piper Aztec. I think that's the position my party is in right now."

Jennings also pointed out the problems that arise from Republican participation in the state's open primaries. He said, "I'm for a primary when the Republicans have a primary, but not when they can come into ours and vote. I'm a Methodist and we don't let the Baptists help us choose our pastor."

Most of the resistance to a convention among steering committee members came from Northern Virginians. Lynn Johnson, Democratic chairperson from the 10th Congressional District, and Raymond Colley, chairman of the Eighth Congressional District, both voted against on immediate decision to have a convention.

Both Johnson and Colley and National Committee member Sandy Duckworth of Fairfax argued that the decision should be delayed until there could be more opportunity for local party workers to express an opinion.

The Democratic Senate field already is a crowded one. Formally announced candidates include State Sen. Hunter B. Andrews of Hampton, former Fairfax Board of Supervisors Chairman Fred Babson, former Fairfax Supervisor Rufus Phillips, and Flora Crater of Falls Church, who ran for lieutenant governor in 1973 as in Independent.

Among those expected to announce soon are State Sen. Clive L. DuVal II of Fairfax and Del. Carrington Williams of Fairfax.

Former Attorney General Andrew P. Miller, who was narrowly defeated by Howell in the Democratic gubernatorial primary this year, is expected to make a decision on the Senate race by the end of the year.

State Sen. Charles Waddell of Loudoun County sent a letter to today's meeting, saying that he is still considering entering the race.

Among the announced and possible candidates, only Miller, Babson and Waddell are decisively in favor of a primary.

Telling the full central committee that he still favors a primary, Miller said, "The Democratic Party over the years has stood for the open door and an open door is what a primary represents."

Miller told the committe members, however, that its choice between a convention or primary would not affect his decision to run.

Babson told the committee members. We are fooling ourselves if we think that by having a convention we will insure that the money will then pour in for our nominee. We will never be able to outspend the Republicans."

Babson said the only way for the Democrats to begin winning statewide elections again is to choose candidates who are in step with the moderate-conservative Virginia electorate.

Andrews also made a veiled call for the party to turn toward more conservative candidates. "It is time we welcome home to Mr. Jefferson's party the thousands upon thousands of Virginians who are at heart Virginia Democrats. In Mr. Jefferson's house there are many rooms for a large family of many viewpoints, but a family wanting to unite and win."

Although the Democrats hold overwhelming majorities in both houses of the General Assembly, the party has won only four statewide elections since 1966. Only one Democratic presidential candidate has carried Virginia since 1948 and the state's congressional delegation of 12 now consists of seven Republicans, four Democrats and one Independent.

Steering committee members also pointed out that one of the problems with a primary is the fact that there is no provision for a runof election. James Begara, Fourth District Democratic chairman, said it is conceivable that in a crowded race the winner of the primary could receive as little as 20 per cent of the vote.In a convention, candidates will be eliminated until one receives a majority of the delegates votes.

The Democratic convention would be held in late May or early June.

The steering committee was told by its treasurer, James Crimmins, that the party now has only $300 in the bank and $1,500 in debts. In his treasurer's report to the full committee, Crimmins left no doubt as to where the party stands. When called upon to make his report he rose and announced in stentorian tones, "Fellow Democrats, we are broke . . ."