The last major hurdle remaining in moving the Kemper Open golf tournament to the Washington area in 1980 was surmounted yesterday with Congressional Country Club members voting to host the PGA Tour event by almost a 9-to-1 margin.

"We now have a mandate from the membership," said Richard G. Kline, president of the River Road club. "Now the board of governors will pursue negotiations with Kemper. I can't envision it being difficult, strenuous or long negotiations.

Congressional and Kemper officials were seeking at least 75 per cent approval by members to move the tournament here. It has been held in Charlotte, N.C., the past 10 years.

Kline said 87 percent of more than 1,000 voters, largest turnout in the club's history, favored the tournament, which has prime dates between the Masters and the U.S. Open. It was held June 1-4 this year.

Steve Lesnik, Kemper vice president, said he expects the Kemper purse to be $400,000 by 1980.

"We consider 87 percent to be very flattering and we're delighted," Lesnik said.

Formal approval is still needed by the Kemper Insurance Co.'s board of directors and by the PGA Tour policy board.

But that approval is seen as no problem because Deane Beman, commissioner of the Bethesda-based PGA Tour, initiated the talks with Kemper about moving the tournament to the Washington area.

Congressional hosted the 1964 U.S. Open Championship and the 1976 PGA Championship. But a PGA Tour event has not been played in this area since the Carling Open at Indian Spring Country Club in the early 1960s. Lesnik said that negotiations - he prefers to call them discussions - with Congressional could begin as early as next week. Exact details on general parameters agreed upon last month remain to be worked out.

Congressional put off further negotiations pending the membership's vote.

"The size of the vote is very indicative," said Kline. 'They wanted a 75 percent majority and so did we. We would not have wanted a divided membership or a divided house. But we don't have to worry about that.

"We don't have a baseball team, but now we have a golf tournament."

The tournament will have a qualifying round on Monday, a practice Tuesday, a pro-am on Wednesday and a 72-hole tournament Thursday through Sunday. In case of a tie, a sudden death playoff will determine the winner.

CBS Television has carried the final two rounds in recent years.

Congressional reportedly will receive an annual guarantee of $250,000 from Kemper. The club also will receive 50 percent of all net profits, with the other 50 percent going to charity.

Still to be negotiated is the length of the contract. It will be for at least three years and possibly five. "I hope," said Kline, "it is a forthcoming marriage that will last a long time."

Proceeds from the pro-amateur prelude, in which Congressional members will have first crack at playing, will go to local charities.

The Kemper has been operating at a loss in Charlotte. This was one reason, in addition to Congressional's reputation as one of America's finest golf courses and the Washington market, that Kemper agreed to Beman's request to seek a new site.

"It was a very substantial deficit," Lesnik said. "But you expect a loss in something like this. It's a business expense. The important thing was that the expenses were increasing and the revenues were staying the same.

"We're got a board of directors to answer to. You try to control the deficit if you can. That's the essential point."