President Carter's election-day registration bill was abruptly pulled from the House calendar yesterday when managers of the legislation found a number of Democrats wavering in their support.

"We have the votes but we don't have a healthy enough majority to inspire our colleagues on the Senate side," said Rep. Frank Thompson Jr. (D-N.J.). "We're just going to sit on it, give it a hard count and improve the majority."

Some Democrats questioned whether there was a majority at all, even in the House.

Rep. Dan Rostenkowski (D-Ill.) said he and other congressment told Carter at a White House meeting yesterday morning that the legislation is opposed by election officials across the country and by Democratic Party Officials in Chicago, where the measure brings memories of past vote frauds.

"I would assume when they pull a bill and the President becomes entwined in it, as he has, that there is some difficulty," Rostenkowski said.

One worry of the administration is that the bill will limp over to the Senate after a narrow victory in the House and be filibustered to death late in the session.

Sen. Strom Thurmond (R-S.C.) warned yesterday that he and others are prepared to engage in "extended debate," the euphemism for a filibuster, if the registration bill reaches the Senate.

Thurmond made his statement at a press conference called by Rep. Philip Crane (R-Ill.), chairman of the American Conservative Union, to announce a poll taken of secretaries of states or state election commissioners. It showed 29 of them opposed the bill, with 12 favoring it and nine others taking no position.

Reportedly, Vice President Mondale has encouraged the President to become personally active in fightine for the legislation. Carter told the Democratic congressmen who met him yesterday that he will write personal letters to the recalcitrant secretaries of state, most of whom are Democrats, urging their support.

Postponement of the legislation is certain to encourage House Republicans, who are nearly solid in opposition to the bill and who have attracted some Southern Democratic support.

Thompson even raised the possibility yesterday the house might approve an amendment by Rep. William Frenzel (R-Minn.), the GOP elections expert, that would make election-day registration totally optional for the states.

"I don't want that amendment and will oppose it but wouldn't die if it were passed," Thompson said.

he added he is confident that most states would adopt the system on their own, suprred by the bill's incentive of 35 cents a voter for election-day registration in federal elections. The bill would have significant GOP support, including Frenzel's, if such an amendment were adopted.

Rostenkowsi suggested another amendment yesterday. It would eliminate election-day registration if 75 per cent of the voters are pre-registered.

And Frenzel said Republicans, who were planning on offering only half a dozen amendments to the bill, may now offer many more, emboldened both by the delay of the legislation and pullback of the bill to relax the Hatch Act after an anti-union amendment was added.

"When you've got a leaky vessel in the fleet, that's were you direct your fire," said Frenzel. "We've just got to put some more arrows in the air."