QuesTech Inc., a McLean professional services firm, said yesterday that it earned $2 million ($1.31 a share) in 1987, compared with $195,000 (13 cents) a year ago, but the big increase was mostly due to accounting adjustments.

The company said the 1987 earnings included $306,000 for a one-time adjustment resulting from changes in the accounting for income taxes, while the 1986 earnings were reduced by a one-time charge of $1.1 million for discontinued operations.

Revenue for the year rose 32 percent, to $62.8 million from $47.5 million.

In the fourth quarter, QuesTech said it earned $939,000 (61 cents), including the $306,000 accounting adjustment.

That compared with a $3,000 loss a year earlier, which included a $595,000 charge for discontinued operations.

Revenue in the quarter rose 21 percent, to $16.5 million from $13.6 million.

CFS Financial Corp., the Fairfax parent of Continental Federal Savings Bank, said it earned $170,000 (6 cents) in the second quarter ended Dec. 31, compared with $1.9 million (62 cents) in the same period a year ago.

Much of the decrease, the company said, was due to an $815,000 loss from the revaluation of an office building the company owns in Tulsa, as well as a $464,000 decline in mortgage-banking income.

For the first half of its fiscal year, CFS earned $186,000 (6 cents), compared with $3.1 million ($1.04) a year earlier, with much of the decline attributable to the same factors.

Total assets of the company rose to $1.1 billion from $1 billion.