An American jogger in spacious, green Gorki Park last week suddenly found himself the centerpiece of an impromptu auction.

Attracted by his western-style sweatsuit and running shoes, three Soviet teen-agers chased the American through crowds of strolling Muscovites, around a circling Ferris wheel, and cornered him in front of a splashing waterfall with one question: "Do you want rubles?"

Soviet leader Mikhail Gorbachev's drive against corruption apparently has not yet affected illegal black market activity in hard currency and western goods here, let alone the so-called multicolored market in the trade of everyday household items or unofficial services ranging from car repair to haircuts.

With few exceptions, economic activity in the Soviet Union is controlled by the state. Stores, restaurants, doctors' and dentists' offices are run and operated by the state. But in the Soviet republic of Estonia, an experiment in loosening the restrictive and often inefficient government-run service industry is taking place, and may continue, according to an article last month in the government newspaper Izvestia.

Soviet citizens provide a growing amount in services na levo, which means "on the left," Russian slang for under the table. The amount is as much as the government provides, according to the Izvestia article. Altogether, 17 million to 20 million Soviets perform 5.5 billion rubles (about $4.6 billion) worth of na levo services a year, the article said.

The "multicolored market" in goods is probably even more vibrant, accounting for 20 to 40 percent of the annual turnover in the Soviet economy, according to western estimates. An American economist dubbed the second economy "multicolored," to indicate that it involves not only illegal black-market goods such as western currencies, but also the gray-market sale of such items as lean meat from the neighborhood butcher, or a plumber's services performed in off-duty hours.

Western goods remain the most popular buys. American name brands, a status symbol in many places in the Soviet Union, are in high demand, the teen-aged black marketeers in Gorki Park said. They underlined their point with bids up to triple the price of goods in the West.

For an Adidas running suit that sold for $79 in the United States, they offered 200 rubles, or the equivalent of about $240; for New Balance shoes, which one said were "much in fashion" in Moscow, 165 rubles ($198), compared with the U.S. price of $59; for a Panasonic mini-cassette player ("Sony is more popular," one teen-ager said), 200 rubles, compared with a purchase price of $80. A Tina Turner cassette tape sold for 15 rubles ($18), compared with $8 in the United States.

Even though most Muscovites seem to own some kind of denim trousers, mostly manufactured in Eastern Europe or Italy, Levis and Wrangler jeans are still hot black market items. Unopened popular western rock albums, traded in curiously arranged deals outside some of Moscow's major record stores, can bring as much as $100 or its equivalent in rubles. The hottest item of all is probably hard currencies, which can sell on the black market for as much as five times their official rate.

Western tourists in the Soviet capital say they occasionally are offered four rubles to the dollar, compared with the official rate of .83 rubles to the dollar.

And when rubles fail to attract sellers on the black market, some of the Soviet sellers bargain with barter goods. One American tourist said that when he rejected rubles for his radio on a recent visit to Leningrad, he was shown a refrigerator stocked with jars of caviar.

In Moscow, where fresh foods are scarce, and shortages of goods ranging from construction materials to toothpaste can become chronic, products more mundane than radios are highly sought after. Two weeks ago, a Moscow taxi rammed into a Soviet car, and in the ensuing brouhaha the taxi driver offered to buy the wrecked chassis to sell the parts.

Demand for services in the Soviet Union remains unfulfilled, according to the article last month in Izvestia, and often they are performed more efficiently under the table than through official channels.

Recently, authorities in Tallin, Estonia, launched a successful experiment to take advantage of the energy and initiative in the na levo service sector, the article said. The state-controlled Tallin radio and television repair service rented one of its workshops to technicians, and after charging each technician a set fee, allowed him to do as much service as he wanted, and keep 70 percent of the extra income.

The results were so remarkable that the experiment has been broadened to some Estonian hairdressing salons, according to the Izvestia article. The television and radio repair brigades have cut the two-week repair period to two days. They even have instituted a local television pickup service for certain areas of rural Estonia. And, conscious of the profits they could earn, they began to operate the business more efficiently.

The Estonian experiment represents a certain relaxation in the Soviet Union's service sector, strictly controlled by the state. It apparently follows recent calls, under Gorbachev, for some industries in outlying Soviet regions to respond to the demand for consumer goods and services with more flexibility.

Black-market activity, however, is strictly illegal, and subject to stiff penalties, including prison sentences, in some cases. Black-market business is usually conducted in clandestine quarters, rather than in Gorki Park.