BOSTON--A coalition including a likely Republican candidate for state treasurer and a radio talk show host proposed a state constitutional amendment yesterday that would limit top elected officials to two terms.

The proposal was unveiled by Joseph D. Malone '78, who may find himself next fall running against incumbent state Treasurer Robert Q. Crane, who has held the office since 1964. Malone and radio talk show host Jerry Williams were joined by Republicans and other supporters below the Paul Revere statue in Boston's North End for a news conference announcing the proposal.

Under the plan, top statewide elected officials, including governor, attorney general, secretary of state and treasurer would be limited to two four-year terms. The House Speaker and Senate President would also be limited to two two-year terms in their top legislative posts.

"Eight is enough," said Malone. "We see politicians breaking trust with the people who elected them because those politicians have remained in office too long."

Williams has boosted his ratings in the past year with heavy criticism of Gov. Michael S. Dukakis and other Democratic leaders for the way they handled the state budget crisis. He said his support for the ballot proposal was a natural extension of his battle against "the centers of power" in Massachusetts.

"People in Massachusetts have had it with high taxes, fees and fines," Williams said. "This is not a radical proposal."

Supporters of the plan noted that 30 states limit the terms of at least some top state offices. Currently, elected state officials can serve indefinitely.

Malone and his backers will first have to raise 51,000 signatures. Then their proposal would require the approval of one-fourth of the Massachusetts House and Senate in two separate constitutional conventions. It would then need majority support on a statewide ballot and could be placed before the voters no sooner than the 1992 election.

Malone has not formally announced his candidacy for treasurer but said he is "pretty certain" he will run. Malone was an unsuccessful challenger of U.S. Sen. Edward M. Kennedy '54-56 (D-Mass.) in 1988.

Political candidates can receive no more than $1000 from any one donor but there is no such limit on contributions to petition drives for ballot questions. Asked if his support for the two-term limit would enable him to receive large contributions from supporters via the fund supporting the ballot drive, Malone said he would not abuse the system.

"I can guarantee there will be no exploitation of the limitation on funds," Malone said.

He added that his likely candidacy for treasurer and the ballot campaign naturally go together, particularly if Crane seeks another term. "I can very easily say that the system is wrong for allowing the treasurer to stay in that long," Malone said.