Geico Corp. yesterday reported a modest 8 percent improvement in last year's operating profits, but Chairman John J. Byrne said earnings were off in the fourth quarter and "the outlook for the property and casualty insurance industry is not good for 1982."

In other earnings reports yesterday, Potomac Electric Power Co. and Virginia Electric and Power Co. reported higher profits for the final month of 1981; United Services Life Companies showed improved quarterly profits, but James River Corp. said its profits slipped.

Geico's annual profits from operations increased to $64.4 million ($2.98 a share) from $59.6 million ($2.59); earnings per share were up more than total earnings because the company bought back some stock last year.

Total profits for the year for the Washington insurance holding company amounted to $83.3 million ($3.85), including a $27.2 million profit from the sale of a subsidiary and an $8.3 million write-off for investment losses. A year earlier, Geico's bottom line totaled $60.8 million ($2.64), including a $1.1 million gain on investments.

Fourth-quarter operating earnings of Geico slipped to $14.8 million from $15.4 million, while earnings per share remained at 70 cents because of the stock repurchase.

Geico Chairman Byrne said car insurance customers submitted fewer claims last year, but the cost of repairs climbed faster than inflation and the company's efforts to expand its auto insurance business were "disappointing." He predicted modest premium growth this year.

Another Washington insuror, United Services Life Companies, boosted its net profits for the year by 25 percent to $16.6 million ($2.93 a share) from $13.3 million ($2.34) while total revenues jumped to $166.6 million from $125.8 million.

An affiliate of International Bank of Washington, United Services reported its operating income climbed to $15.3 million ($2.71) from $12.7 million ($2.34), while investment profits climbed to $1.25 million from $341,000.

Fourth-quarter net income was $5.2 million (92 cents) on revenues of almost $54 million, up from $3.5 million (62 cents) on revenues of $39.9 million.

Reporting on monthly revenues for January, Vepco said it earned $35.7 million (29.5 cents a share) on revenues of $235.9 million, up from profits of $26 million (21.2 cents) on revenues of $206.9 million in January 1981.

For the latest 12-month period, Vepco earnings climbed to $247.5 million ($1.86) on revenues of $2.2 billion from $246.4 million ($1.97) on revenues of $2.1 billion.

Pepco's January net crept upward by $45,000 to $8.1 million, but that wasn't enough to boost earnings per share above last year's 15 cents. Revenues of the Washington utility climbed to $87 million from $79.6 million.

Pepco's profits for the latest 12 months climbed a penny a share to $109.7 million ($2.13) from $105.3 million ($2.12) while revenues jumped past $1 billion from $875 million.

James River Corp. reported its fiscal third-quarter net slipped to $4.4 million (35 cents a share) from $5.2 million (45 cents), while sales fell to $184.3 million from $187.3 million. For the nine months through Jan. 24, James River earned $15.6 million ($1.33) on revenues of $565.6 million compared with $10.3 million ($1.11) on sales of $365.6 million last year.