Virginia Republican Lt. Gov. John N. Dalton opened three days of campaigning for governor in the Washington suburbs yesterday, claiming he is gaining on Democrat Henry E. Howell and acknowledging that, until late August, he was having difficulty raising campaign funds.

"We're generating funds now," he said after a television taping at WTOP-TV in Washington, but he added: "We've still got a good bit yet to go."

Dalton consistently refused to say yesterday just how much more money the Dalton campaign needs, although he said at one point he hopes to raise "more than" the $1.3 million his campaign had initially planned to spend in the race. He also refused to give specific figures, but said repeatedly that new polling data he received last Friday showed he has overcome Howell's early and "substantial" lead over him.

Dalton's admission that his campaign had encountered fund-raising problems came as something of a surprise. Howell's supporters have said they believed Dalton had raised $1 million since the June 14 Democratic primary because he had access to many conservative businessmen who supported Andrew P. Miller, who lost to Howell in the primary, as well as to traditional Republican donors.

At a Virginia Beach reception Monday night Dalton had alluded to the financial troubles when he told the group of about 100, "If we meet out objectives we need to raise $600,000 to $700,000 in the last five weeks of the campaign."

He then disclosed that he and his wife had borrowed $90,000 from a Virginia bank for the campaign. Yesterday he said that when his first finance report is disclosed next week, it will show other loans as well.

But Dalton said both the tempo of his campaign and his fund raising has increased markedly since late August when Howell attacked him during a meeting of the state AFL-CIO convention at Roanoke.

"Week before last, we put $111,000 in the bank and last week we put $85,000 in the bank," he told the Virginia Beach gathering. But that was a precise as he got.

Although Dalton said a late September poll shows he has gained on Howell, it also shows that a large portion of the Virginia electorate remains undecided over the governor's race and that he is "still behind" Howell. "We think at this point the race will be decided by a margin of within three percentage points," he said.