BANGOR — Just after sunrise on a day in late May, a politician wearing a red scrub top greeted hospital workers on their way into work at Eastern Maine Medical Center.

“Troy Jackson, I’m running for Congress,” he said, using the line over and over while extending his hand to scores of employees. “I’d really appreciate your vote June 10th.”

Most shook the hand of the candidate, who is running in the Democratic primary for the 2nd Congressional District seat. Some stopped and talked. Others rushed by, running late for work. Then, members of the Maine State Nurses Association, the statewide union that has endorsed Jackson, handed the candidate’s leaflets to employees.

“We don’t have the big money that the other side has,” said Cokie Giles, the union’s president. “We have the manpower.”

That may be so, but on money, Giles’ remark is probably an understatement going into Tuesday’s primary.

The fight for voters that has gone on for months will ramp up this weekend and into Tuesday, with Democratic and Republican candidates criss-crossing the district and volunteers and staffers making thousands of calls and knocking on doors.

The same day Jackson started in Bangor ended with his campaign reporting having just $19,000 left to spend, behind primary opponent Emily Cain’s $145,000. He doesn’t have an ad on television; she has been on the air for more than two weeks.

In addition, outside groups are spending hundreds of thousands of dollars to support Cain, a state senator from Orono. One of them released a poll Wednesday saying Jackson, the Maine Senate majority leader from Allagash, is 35 percentage points behind her.

“Based on everything we can see and what we know, I think she’s got a huge edge going into Tuesday’s vote,” said Mark Brewer, a political science professor at the University of Maine in Orono.

The Republican race between Kevin Raye and Bruce Poliquin looks like it will be far closer than the Cain-Jackson matchup.

There has been no recent public polling in the race between Raye, a former state Senate president from Perry, and Poliquin, a former state treasurer from Oakland, for the seat to be vacated by Democratic U.S. Rep. Mike Michaud, who is running for governor.

Raye has run for the seat twice and has hit Poliquin hard on his recent move to the district, while Poliquin has run ads for weeks against the more-moderate Raye, with one calling him a “liberal politician.”

Jackson will get some support from unions, led by the Maine AFL-CIO, a coalition of 160 unions and 30,000 workers that has endorsed him and helped organize more than 20 leafleting sessions outside workplaces, according to Matt Schlobohm, executive director of the labor group.

But more important is Jackson’s team: Despite his low cash reserves, campaign spokesman Alan Brewer said Jackson has invested in a get-out-the-vote effort fueled by staff and 100 volunteers who hope to make 85,000 calls to potential voters by Tuesday.

That could be about as many people who turn out for the primary in both parties. Secretary of State Matthew Dunlap said statewide, between 13 percent and 15 percent of those 18 and older normally vote in primaries. In the 2nd District, 15 percent of the voter-age population is just under 80,000 people.

Cain’s campaign is aiming at a number that would reflect the number of Democrats in the district. Spokesman Dan Cashman wouldn’t give the target number of calls, but said as of early Thursday, Cain’s team had surpassed 20,000 calls using about 100 volunteers, while Alan Brewer said Jackson’s team passed 30,000 last week.

“The other side has access to Wall Street money and invested in a media campaign,” the Jackson spokesman said. “We invested in a field operation and a get-out-the-vote effort.”

However, Cashman said Cain’s campaign is getting positive reactions on the phones that reflect the polling in the race.

Poliquin’s campaign wouldn’t discuss tactics, but Michael Leavitt, spokesman for Raye’s campaign, said the candidate will have 225 volunteers working over the next few days, and he said the campaign has called about 26,000 potential Republican voters so far.

“Kevin is very excited and, quite frankly, humbled, by the number of volunteers and the amount of support he’s received,” Leavitt said.

Brewer, the political scientist, said he doesn’t know exactly how to read the Republican race, which he expects will be close. He said Raye is likely more electable in the general election, but the low-turnout partisan primary audience often leans more conservative, which may work for Poliquin.

But he said despite Jackson’s field operation, the path to victory for him over Cain looks difficult. “If he’s got something left in the tank or another club in the bag, now’s the time to use it,” the political scientist said.