The admiral who was Jimmy Carter's boss and teacher will tear into "double dippers" today when he leads off House hearings into the status of 141,000 government workers who draw both pay and pension checks from Uncle Sam at the same time.

Hyman G. Rockover will take the stand before the House investigations subcommittee that is looking for ways to curtail or eliminate dual payments to federal workers. Adm. Rickover, not one to mince workds, is expected to endorse legislation that would modify or eliminate the dual compensation laws. They allow retired reserve officers and enlisted personnel to draw full military pensions and full civil service salaries.

The selection of Rickover as the leadoff witness obviously was no accident. Committee chairman Robert N.C. Nix (D-Pa.) feels strongly that the dual compensation system ought to be revised. And getting somebody like Rickover - who attracts journalist and headlines - will guarantee a public spotlight and debate on the emotional issue.

The fact that Rickover carries great weight with President Carter will also help to build congressional support for changes in the dual compensation law. That could more than offset the lobby favoring dual compensation in the House made up, in large part, by members of Congress who are themselves military retirees or reservists who are or will be eligible for two federal paychecks too.

Rickover could, but probably will not point out the fact that the dual compensation law discriminates against regulars like himself (Annapolis 22). They are allowed to draw only a portion of their retired pay of they go into government as civilians. Reserve officer retirees and all enlisted personnel get to keep all of their military and civilian salaries.

Nix, who says there are at least 10 admirals, retired admirals and generals working for the government drawing $80,000 or more in pay and pension, also wants to explore the "buddy system." That, civilian federal workers claim is when military retirees in government gather fellow retirees around them taking the best jobs and promoting each other at the expense of nonmilitary retirees. There are more than 13,000 retired military personnel now working at fedderal civilian jobs here. How many of them are buddies isn't known.

The military retirees will fight back, and they will have their day before the Nix subcommittee. They will point out that the bulk of the retirees in government are enlisted personnel with small pensions - people who had to retire because of the military system and who must work elsewhere to support families.

The retirees also argue that the government benefits from their military years of experience and training, and that it is cheaper for Uncle Sam to hire them directly as civilians (even paying pensions) than to hire them indirectly as contract employees of some private firm. It sin't an easy issue to decide: but it clearly is an emotional one. Probably it is the hottest item on the bureaucratic very beat this year.