PRESIDENT CARTER tends to turn almost reflexively to his most trusted adviser, Atlanta attorney Charles H. Kirbo, when tough problems require especially careful handling and more top-level attention than the president himself can give. In putting the nearly bottomless scandal at the General Services Administration in that category, Mr. Carter is absolutely right. The question is whether Mr. Kribo's particular brand of detachment from the Washington scene equips him to make the kind of judgments and provide the kind of advice Mr. Carter is most likely to need.

For one thing, Mr. Kirbo has no standing in the chain of command; he is not officially accountable to anybody. So it was hardly surprising that his appearance on the scene immediately sparked concerns about possible White House interference with the current investigations of alleged bribes, kickbacks and other crimes. Mr. Carter evidently did not anticipate how quickly the specter of Watergate-type obstructions of justice can still arise. Such fears may be entirely unfounded; at least so far, nobody has suggested that the Carter White House has any wrongdoings at GSA to cover up. But the principle involved is sound in any case. There is no proper place in a criminal investigation for an unofficial White House overseer - especially one who, no matter how close to the president, is still a private citizen and a lawyer with corporate clients who do business with GSA.

Attorney General Griffin Bell recognizes the need to avoid even the slightest appearance of impropriety.He said firmly last week that Mr. Kirbo will have "no role" in he Justice Department's investigation, no access to information derived from criminal probes and no involvment in any prosecutions. Mr Kirbo's role, as clarified, will be to counsel and bolster GSA Administrator Jay Solomon on the non-prosecutorial aspects of cleaning up the federal housekeeping agency.

That is, as Mr. Solomon put it, a "monumental job." Nearly every day there is more evidence of how habitual mismanagement and extravagance of GSA have been, and how collusive the relationships among various officials, contractors and friendly politicians have become. Even with strong White House support, it will take years to make all of the desirable policy and personnel changes at headquarters and in the field. To the extent that Mr. Kirbo's presence is a token of presidential concern and seriousness of purpose, it can do no harm, and perhaps even some good.

But more than a demonstration of firm presidential commitment is required in matters of this kind. Considerable political adroitness - of the sort that was conspicuously absent in the president's handling of the transfer of Robert Griffin, Speaker Thomas O'Neill's protege, fron the No. 2 job at GSA - is also heavily in demand. And that raises further question about Mr. Kirbo's effectiveness as the administration's principal troubleshooter. What Mr. Kirbo's repeated rides to the rescue from his Atlanta law firm would seem to suggest is that there is something missing from the permanent inner circle at the White House. It's not a case of having nobody there whom the president trusts. And it's not as if there were no experienced old hands around. What's missing, perhaps, is a trusted intimate like Charles Kirbo, on regular duty, who is also seasoned veteran of the political and bureaucratic world of Washington.