A proposal to make all of the divided city of Takoma Park part of Montgomery County won the backing of that county's House delegates today amid charges that the favorable vote was tantamount to a political endorsement of the city's outspoken mayor just in time for Tuesday's election.

Today's 10-to-4 vote in Montgomery's delegation meeting also raised an old rivalry with neighboring Prince George's, where many delegates see the move as a simple land-grab. Takoma Park is now split, with two-thirds in Montgomery County and the rest in Prince George's.

Takoma Park's fiesty and often caustic mayor, Sammie Abbott, is in a tight reelection race against Ronald J. Wylie, the Prince George's attorney he defeated two years ago. Abbott has made unification a major plank of his reelection drive, as he has in his last two mayoral races.

The division of the city creates what some of its residents call an administrative nightmare, since two separate county governments and their distinct bureaucracies must be dealt with.

So Abbott got Del. Stewart Bainum Jr. (D-Montgomery) to propose a bill calling for a November unification referendum among the Prince George's residents of Takoma Park. After four public hearings this summer, they would vote on whether to become part of Montgomery. The bill is given little chance for passage since it is opposed by Prince George's.

Critics of unification--from Wylie to Prince George's delegates not anxious to cede territory to Montgomery--say the step could create problems.

Wylie called today's swift vote "part of that incest that exists between the mayor and his political buddies trying to get him through his reelection effort.