A gas company lobbyist who questioned Secretary of Interior James G. Watt's comment that the political world is divided between "liberals and Americans" was fired from his job after a Watt aide wrote the lobbyist's boss that the secretary was "surprised" the lobbyist would do such a thing.

Timothy L. Donohoe, 36, said yesterday he was fired from his $30,000-a-year job as a Washington representative for Enserch, a Dallas-based natural gas company, earlier this month for his "lack of judgment."

On Dec. 1, Donohoe said, he had written Watt about a report in the previous day's Washington Post, quoting a Fresno Bee story about a speech Watt had made to a group of California farmers. In the speech, Watt said, "I never use the words Republicans and Democrats. It's liberals and Americans."

In the letter, written on private stationery with his office address, Donohoe asked Watt to "kindly furnish a further clarification of your remarks . . . which could be construed as questioning the patriotism of certain individuals."

"For the record," he added, "I am an American and a liberal. And the Washington lobbyist for a $3 billion energy concern."

Donohoe said he received no reply, but was called in two weeks ago by his boss, Candice J. Shy, and shown a copy of his letter and one written on Dec. 15 by Stanley W. Hulett, an assistant to Watt and director of Interior's congressional affairs. Hulett's letter was to William C. McCord, chairman and chief executive officer of Enserch.

Hulett wrote: "I thought you might find interesting a copy of a letter delivered by hand to the secretary by your Washington representative.

"The issue Mr. Donohoe questions was part of a joke the secretary told at a political fund-raiser and is certainly not meant to question the patriotism of anyone.

"The secretary is, frankly, surprised at Mr. Donohoe's representation in the attached letter."

Donohoe said yesterday that Shy told him that he was being fired for his "lack of judgment" in writing the letter. Cleaning out his desk yesterday, he said he was still in a state of "shock and disbelief."

William T. Satterwhite, senior vice president and general counsel for Enserch, last night confirmed the basic facts in Donohoe's account but said, "I believe it would be inappropriate to comment further."

Interior's Hulett was not available for comment, but Tom DeRocco, acting deputy director of the office of public affairs at Interior, said, "The letter will have to speak for itself."

Rep. Charles Wilson (D-Tex.), on whose staff Donohoe had worked for seven years before joining Enserch 14 months ago, said he was disturbed by the incident.

Wilson said the fact that Hulett had "taken the trouble to track down" Donohoe's employer and "sent a letter to the chairman of the board, instead of to Tim . . . represents the smallness, the pettiness and the hatefulness people have been accusing Watt of. I have been a defender of Watt, but this represents a kind of vengefulness I hate to see."

DeRocco would not comment on Wilson's remarks.