Mike Carter spent the week before the historic 100th running of the Boston Marathon — what he believes will be something akin to a trip to Mecca — caught in a funk.

Just a week away from today’s race, his 14th marathon and fourth Boston, the man from Machias was struggling with a case of the runner’s blues.

Carter, 45, has had a frustrating time at Boston before, and the months leading up to the race have been filled with setbacks. He injured his hamstring in December in a snowmobile accident and is in no condition to run.

After he qualified for Boston in last year’s Portland Marathon, the winter became a challenge to stay in shape so he could run Boston. Now, Carter just hopes to finish.

“It’s important to me to run the 100th,” Carter said, “not so much the marathon as the hoopla. I haven’t run a marathon in a couple of years. I did very little training to qualify in Portland last fall. I ran about 25 miles a week just to get through it.”

But Carter’s friends and fans are not surprised by the resolve of the man, who has had 17 knee operations, to keep running.

“He would feel he had blown it if he didn’t run it, because of the importance,” said Brewer track coach Dave Jeffrey, who befriended Carter eight years ago after they met through a road-racing crony.

“He’s had a lot of heartbreak there,” Jeffrey said. “He feels he should run it, because it’s the one to run. It doesn’t matter if he runs fast. He just wants to be a part of it.”

Fred Merriam, president of the local Sub 5 Track Club, can vouch that the running-worn Carter is a bit extreme, even among eccentric road racers.

“He’s crazy,” said Merriam, who has been running road races since 1980. “We ran a 10-mile race at Cape Elizabeth in February and it was 6 degrees out, there was a wind chill of 15 miles an hour the last few miles, and Mike ran in shorts. He was the only one.”

Yet, while the road racer’s sense of obligation demands Carter run Boston, the world’s oldest annual marathon, he hoped the celebratory event would offer more, and he’s afraid it won’t.

“It’s quite an experience, especially for a guy from rural Maine who goes to marathons with just 200 runners. It’s a love-hate relationship,” Carter said of his feelings for Boston’s logjams, narrow streets and manic fans.

There are 37,500 official entrants in today’s race, and 1.5 million spectators are expected.

“Some people think it’s really exciting. I’m really trying to work on my attitude. I question how much fun it will be. I’m quite competitive, but I won’t be able to run fast.”

Yet the lunacy of the long-distance runner drives Carter, and the centennial celebration calls him.

“I’ll find a way to finish if it takes me six hours,” Carter said. “If it weren’t for Boston, I would have run less this winter. If it weren’t the 100th, I wouldn’t go. I’m in no condition to race.”

Carter has been slowed in Boston before, and that’s the basis of his disdain for the race. The mammoth crowd, the waiting, the isolation — for him, Boston is claustrophobia with a sense of seclusion.

“In the races I’ve run in Maine, my wife, Catherine, she’s my support crew. She brings T-shirts, bananas, drinks, literally drives every other mile with aid and support,” Carter said. “I do well at those races. But at Boston, I kiss her goodbye at the hotel and hope to find her at the finish line.”

The last two times Carter ran Boston, he said, it took him almost two minutes just to reach the starting line because of the flood of runners clogging the race route. This year’s start will be no different.

“It’s very frustrating,” Carter said. “It’s like a long caterpillar, starting and stopping. Everyone is attached.”

Then there are the renegades.

“There will be bandits,” Carter said. “There always are. This year, with it being the 100th, several people have written running magazines saying they are ticked off because they didn’t qualify or get a lottery number, and they insist they will be there anyway.”

And screamers.

“I detest going through Wellesley. The high-pitched squeal of the girls is just too much,” Carter said of the well-known section where the college students cheer on the runners.

“Everyone told me it was so much to look forward to, but with them screaming their bloody guts out it gave me a headache.”

And, with much of the race a downhill run, Carter dreads the shock to his quadriceps, the large muscle at the front of the thigh. Some year, he swears, he’ll prepare for the race by training on downhills. It would mean more than satisfaction to Carter to run well at Boston.

“The two years I’ve run it I’ve had a disappointing performance,” Carter said of his 3 hour, 26 minute and 3 hour, 14 minute performances. “I never run Boston well. I need to get that monkey off my back. But this won’t be the year.”

Adversity, however, seems to be Carter’s biggest fan. The last three years for him have been an adventure in injuries.

A few years ago, doctors told Carter he couldn’t run because of a hernia. It turned out to be a stress fracture, but Carter found that out only after going and running.

“He hadn’t taken a step in about five months,” Jeffrey said, “but the doctor couldn’t find what was wrong. So he goes out three days before his next appointment and runs five miles, eight miles the next, and the day before he runs up a mountain. He wanted to be in such pain so the doctor could find something wrong with him. He then felt fine and was back running.”

Jeffrey seems to appreciate, if not quite understand, Carter’s unique logic in living with pain.

“He’s very, very tough. He can withstand more than most,” Jeffrey said.

“Running for him is very important. He’s a running fanatic. He loves the people, he loves going out for a run and beating on everybody and himself.”

So the competitor in Carter has stepped aside as the survivor works on making it to the finish.

On March 24, Carter returned to playing doctor again when, in a 15-mile race he ran in Readfield, he reinjured his hamstring. He intended to run at an easy 8-minute pace to test his hamstring but, in his excitement, ended up running a 7 minute, 10 second pace.

“I injured my Achilles’ tendon. I pulled my hamstring on the same leg, creating other problems,” Carter said. “I think I have a serious injury. I think I need help, but there’s no time now.

“Basically, I’m just hoping to finish.”

Despite it all, Carter knows some things, no matter how painful, are too sweet to miss.

“I don’t want to DNF again,” Carter said of the one time he didn’t finish a marathon. “I don’t want this to be my second [DNF]. Especially because it’s the 100th.”

But Carter’s running comrades don’t doubt he’ll finish. In their estimation, he’s the king of pain.

“Well, it’s not like he’s going to limp for 26 miles,” Jeffrey said. “More than anything else, what’s facing him, to Michael, is the challenge.”

And, Jeffrey added, Carter’s goal is not unique.

“A lot of people are not in shape. But a lot of people feel they have to race Boston, they feel this is the one they can’t miss,” he said.