President Carter yesterday asked all U.S. companies scheduled to send the Summer Olympics such products as pole vault pits, scoring devices and even baggage X-ray equipment to voluntarily stop shipping their merchandise to the Moscow Games.

Carter's action, affecting between $15 million and $20 million in merchandise, from Olympic chewing gum to Coca-Cola, is the latest step by Carter in response to the Soviet invasion of Afghanistan. White House officials said it was meant to appease Olympic athletes whom Carter has asked not to participate in the Games.

At present, the president is merely requesting companies not to participate.

White House and Commerce Department officials will call the individual companies involved to request their compliance, administration officials said.

However "the question of whether the government should exercise its legal powers to ban Olympic-related exports remains under advisement," a Commerce statement said. Products that would be sent to the Olympics are exported under general licenses rather than validated licenses, which require prior Commerce approval.

The government could place the Olympic items under validated licenses as it did with agricultural products banned from exports to Russia but that move is still being studied, a White House official said last night.

"From a a public relations standpoint it would be disastrous to go around the president's request," a spokesman fro AMF sporting goods said yesterday. t"When the team's not going, you'd really be looking for bad publicity."

One of many questions left open is whether Carter's request will affect companies who ship materials from foreign subsidiaries. A White House spokesman said that if a company complies with the spirit of the president's request it wouldn't ship any goods from its foreign outlets.

A Commerce Department official acknowledged last night that some of the equipment Carter is requesting be withheld may be obtained from other countries and a large part of that equipment already may have been shipped.

"This is fairly late in the process that this action is being taken," the officials said. "If the companies respond to the president's request, it would have some effect."

The Coca-Cola Co. had planned to distribute Coca-Cola as the official Olympic drink during the Games and also use that advantage to meet the Pepsi challenge. A company spokesman said the company had no comment on Carter's request.

Officials of AMF, which supplies equipment to other countries' teams said they weren't sure what equipment, if any, they would be supplying to the Olympics.

In addition to pole vaulters, Olympic swimmers may be left high and dry because Carter's request would cover the ANTI Co. and Hind Wells, Inc. which are supposed to supply swimming pool equipment. The AM-PRO Co. has a contract to supply landing pits for the high-jump and pole vaulting events.

Commerce and White House officials said other equipment affected would be the Wrigley Co. chewing gum, Pitney Bowes, which was supposed to supply postal equipment, and makers of X-ray machinery for inspecting baggage, track paraphernalia, scoring devices, small computers, and other sports equipment and clothing.

"With the withdrawal of the Americans [athletes] it all went up in smoke anyway," said a Wrigley spokesman of that firm's plans to have the official Olympic chewing gum.