Mobil Corp. reported higher earnings for the final quarter and the full year 1976. The company is the nation's third largest oil producer.

Earnings for 1976, boosted by the company's mid-year acquisition of the remaining 46 per cent of Marcor, Inc., increased by 16.3 per cent to $942 million ($9.07 a share). A year earlier, when Mobil owned only 54 per cent of Marcor, corporate earnings were $810 million, ($7.95). Revenues totaled $27.7 billion in 1976 and $22.4 billion in 1975.

Fourth-quarter corporate earnings rose by 33.5 per cent to $263 million ($2.49) from $197 million ($1.93) a year earlier.

The corporation said fourth-quarter revenue figures were not available.

Oil-related sales and earnings by Mobil Oil Corp. continued to dominate the corporation's business, despite its purchase on July 1, 1976, of Marcor, Inc., and its subsidiaries, Montgomery Ward and Container Corp.

Oil revenues accounted for $24.9 billion, or 89 per cent of the corporation's revenues in 1976. In 1975, oil revenues were $22.4 billion. Mobil's worldwide oil earnings rose by 14 per cent to $774 million in 1976 from $681 million in 1975.

Typical of experience of most international oil companies, oil business was nore profitable in the United States last year than elsewhere because the rate of economic recovery was faster here.

Mobil's U.S. petroleum earnings surged 250 per cent to $434 million last year from $171 million the year before. In 1976, domestic oil earnings accounted for 56 per cent of Mobil Corp's profits against 25 per cent of its profits the year before.

Overseas profits were particularly weak in the first half of the year, the corporation reported.

However, the company's over-all profits on each gallon of petroleum product sold advanced to 1.6 cents last year from 1.4 cents a year earlier.

Mobil's report said profits at Montgomery Ward and Container Corp. were up for the year, too.

Standard Oil Co. of California earned up $880 million ($5.18 a share) in 1976, up 14 per cent from $773 million ($4.55) in 1975, the company reported.

Standard said its fourth-quarter earnings were up 29 per cent from the same period in the previous year to $268 million ($1.58) from $207 million ($1.22).

Revenues for 1976 were $20.6 billion, up from $18.2 billion in 1975, and revenues for the quarter were $5.7 billion compared with $4.5 billion in the same quarter the previous year.

Board chairman Harold J. Haynes attributed the earnings improvement to "higher worldwide oil production, increased sales of petroleum products and natural gas in the United States, stable domestic product prices, and more realistic natural gas prices."

Occidental Petroleum Corp. earned $2.75 a share in 1976, up from $2.64 in 1975, the company estimated yesterday in a preliminary report.

Net income was about $183 million, up 6.4 per cent from 1975's net of $172 million.

Gross revenues were not estimated.

Fourth-quarter profit was estimated at $71 million ($1.12 a share), up from $17.7 million (20 cents) a year earlier when earnings were heavily penalized by writeoffs on operations in Venezuela and Nigeria.

The company said that depressed markets for steam coal, as well as weakened profit margins on coal, were more than offset by higher earnings on oil and gas.

Sun Co., the nation's 14th largest oil firm, announced that its 1976 earnings increased by 62 per cent over the previous year, from $3.63 a fully diluted share in 1975 to $5.88.

The firm's fourth-quarter earnings were up 43 per cent over the 1975 period of $1.41 a share on a fully diluted basis.

Fourth-quarter earnings of $485 million amounted to $1.77 a common share after deductions of dividends on preferred stock, Sun chairman, H. Robert Sharbaugh said.

For the full year, he said earnings totaled $365 million ($7.33 a primary share), up from the 1975 figure of $220 million of ($4.20).

Revenues were $1.6 billion for the fourth-quarter and $5.5 billion for the full year. Figures for the comparable 1975 periods were $1.3 billion and $4.4 billion.

Sharbaugh said improved domestic marketing and refining operations, coupled with a recovery in the U.S. economy, were responsible for the improved 1976 performance.

Cities Service Co., a major oil producer, earned $7.98 a share in 1976, up from $5.12 a year ago. Net income was $217 million, up 58 per cent from the $137.7 million earned a year earlier.

Fourth-quarter net was up 28 per cent at $59.6 million ($2.18 a share) from $46.6 million ($1.73) the previous year.

The 1976 profit represented a 12.7 per cent return on stockholders equity, a substantial improvement over the previous year. But chairman Robert V. Sellers said this return was relatively low considering the petroleum industry's need for reinvestment capital. The company's capital outlays in 1976 were $525 million.

The company had continuing operating losses on the Copperhill, Tenn., mining and chemical complex.

Ashland Oil, Inc., earned $1.56 a share in its first quarter ended Dec. 31, up from $1.54 a year ago. Net income was $43.3 million compared with $40.8 million a year ago.

Chairman Orrin E. Atkins said the improvement was attributable to higher operating levels and better price margins on coal and chemicals, together with increased tax credits.

Atkins said exploration earnings were affected by the loss of profits from the company's Venezuelan holdings, which were nationalized at the end of the 1975 first quarter.