To cut overtime costs for two days this week, the Portland Fire Department shut down its ambulance at the Munjoy Hill fire station, which gets the fewest ambulance calls of any station in the city, particularly at night, the acting fire chief said Friday.

Acting Fire Chief David Jackson said the ambulance was back in service for half of Friday, but the question of whether it will continue to run hasn’t been resolved. “It’s day to day,” he said.

The conspicuous “closed per city govt.” sign that was outside the station’s ambulance bay Wednesday and Thursday was gone Friday.

Cutting the hours at Munjoy Station, at 134 Congress St., is part of a longer-term cost-cutting measure, said Jackson, who has been in the position since Oct. 20, after the resignation of Fire Chief Jerome LaMoria.

Jackson said the city has often kept the ambulance in service by paying firefighters overtime, but the station covering the east end of Portland’s peninsula has received the lowest number of ambulance calls.

“We’re not even halfway through our budget year, and we’ve spent over half of the overtime line just trying to cover shifts,” Jackson said.

He said he could not provide data on the number of calls for service until City Hall reopens next week. City Hall was closed Friday for the long Thanksgiving weekend.

Firefighters at Munjoy Station staffed the ambulance from 8 a.m. to 8 p.m. Friday, a time of day when it gets more calls than overnight.

Jackson said the department will continue to fill as many shifts as it can without dipping unnecessarily into the overtime budget. The department’s overall $16.5 million budget includes about $1 million for overtime expenses, according to the budget posted on the city website.

Jackson said the ambulance at Munjoy Station was transferred there about six months ago from Central Station, and the department has struggled to staff it during that time. The department has been operating with fewer than its allocated 234 firefighters.

The department now has 220 firefighters, with 12 new recruits scheduled to join the force Dec. 5. But Jackson said two firefighters are scheduled to retire Dec. 6, and more will retire next year.

Firefighters who were working at Munjoy Station on Friday declined to comment on the situation.

The four pieces of the wooden “closed” sign that was propped up against the bay door Wednesday and Thursday were inside the station Friday. The boards were neatly stacked against the bay wall, within easy reach if firefighters wanted to post them outside in the future.

Jackson said he decided to put the Munjoy Station ambulance on a “day-to-day” status after consulting with City Manager Jon Jennings, who has been in his position for only three months.

Jennings could not be reached for comment Friday.

Mayor-elect Ethan Strimling said Friday that he does not want to comment on ongoing issues until he succeeds Mayor Michael Brennan in December.

“I’m not in the loop on it yet,” Strimling said of the fire department funding issue.

Jackson said people in the Munjoy Hill area should not take the part-time ambulance service at Munjoy Station to mean they don’t have service.

All ambulance calls are routed through the emergency medical dispatch system, which draws the ambulance that’s closest to the location of the call.

The next-closest ambulance for Munjoy Hill is at Central Fire Station at 380 Congress St. Ambulances also are stationed at the North Deering station on Allen Avenue, and elsewhere in the city.

As an example, Jackson said, if a call came for an ambulance on Brighton Avenue and the ambulance from the nearest station, on Stevens Avenue, was on another call, the department could dispatch an ambulance from Bramhall Station, at 784 Congress St.

The Portland Fire Department has an average response time of 3½ minutes for ambulance calls, well below the nationally recommended response time of five minutes, Jackson said.

The department has long dealt with high overtime costs, an issue that has drawn the attention of some city councilors, particularly at budget time.

In 2013, a consultant advised the city to hire more full-time firefighters to reduce overtime spending, but not everyone was satisfied with that recommendation. Portland already has more firefighters per capita that any other medium-sized city in New England, according to an analysis by the Portland Press Herald.