The Mayweathers are in this fight together

The ride of a lifetime that is fatherhood began for Floyd Mayweather Sr. by pushing a stroller around his former Grand Rapids, Mich., neighborhood.

“Used to walk my son every day — maybe someone would think I was some kind of gay person or something — but every day I walked him everywhere with me,” Mayweather said. “You see me, you see the stroller. That was my first kid, I was so overly joyed to have him.”

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The elder Mayweather, a pro boxer himself who lost to Sugar Ray Leonard in 1978, admits, “I always wanted my kid to be a fighter.”

And when baby Floyd Jr. would get set in his bed at home, his dad would show him how to punch: right hand, left hand, right, left.

“I put gloves on little Floyd when he was around 11 months,” his dad said. “Something that really surprised me was that little Floyd was in the bed alone throwing some shots. The Lord as my witness, I saw him. From that point on, I’ve been working with him, working with him.”

His son is now widely considered to be the best boxer in the world. Mayweather Jr. will put his unbeaten record (47-0, 26 KOs) to its stiffest test yet Saturday night against eight-division world champion Manny Pacquiao at the MGM Grand in Las Vegas in a bout that’s expected to shatter all boxing revenue records.

“I was breeded to be a fighter,” Mayweather Jr. said. “I take my hat off to my father … . It all started with my father. If it wasn’t for him, I wouldn’t be here.”

Mayweather Sr. will be there too, again in his son’s corner as lead trainer.

The Mayweathers have had a notoriously stormy relationship that’s resulted in extended splits, first due to the father’s five-year imprisonment more than 20 years ago on a drug trafficking conviction, and later due to fallings out because of their sizable egos.

“He might’ve felt it was my fault, I might’ve thought it was his,” Mayweather Sr. says. “He’s still my son.”

When things were bad between them, the younger Mayweather relied on his uncle, former super-lightweight champion Roger Mayweather, to train him. But after Mayweather was visibly marked up in a 2012 victory over Miguel Cotto, and with his uncle ailing, the father and son reunited.

Mayweather is 4-0 since, outclassing younger Robert Guerrero, Saul “Canelo” Alvarez and Marcos Maidana (twice) thanks to evasiveness and precision punching and the defense-first counsel of his father/trainer.

What matters most to both is that Mayweather Jr., at 38, is closing his career with the man who first envisioned it.

“It’s just a blessing,” Mayweather Jr. said. “I come in the gym and work. I have tunnel vision. I try to focus on doing my job and being the best at my job. My father deserves credit because I wouldn’t be a fighter if it wasn’t for my father.”

The two Mayweathers have had, to say the least, a complex relationship that dates to the son’s early childhood.

The elder Mayweather has occasionally told the story of a day in their Grand Rapids home when he got into a scrape with the late brother of Floyd Jr.’s mother. Mayweather Sr. picked up his crying toddler son as the man came back inside to answer the conflict by pointing a shotgun at Mayweather Sr.’s head.

The dad kept holding young Floyd. “My son’s in my arms and … [his mother is] telling me to give her the baby [with her brother holding] a shotgun on me,” Mayweather Sr. said. “He went on and shot me [in the leg] anyway with the baby in my hand. So who would be crazy enough to say, ‘Here’s the baby?’ I give the baby … I’m dead. That [bullet] would’ve been right here, in my head.

“You’re not going to get this baby because this is my only shield. … I used my mind, and if I hadn’t used my mind, I wouldn’t be here right now.”

Mayweather Jr.’s own household unrest landed him in jail for nearly three months in 2012 for a battery domestic violence conviction against the mother of his three children. It was a soul-searching experience that preceded the reunion with his father.

The elder Mayweather has trained other celebrated boxers, including Oscar De La Hoya. He worked in Englishman Ricky Hatton’s corner for just one fight, a second-round knockout loss to Pacquiao in 2009.

Pacquiao’s trainer Freddie Roach has made light of Mayweather Sr.’s ability as a trainer, saying he’d be more concerned if Roger was back in charge for this fight.

“The dad gets too excited in the corner, doesn’t give good direction,” Roach said. “I’m very happy he’s there, to be honest with you.

“Floyd trained himself mostly — learned by watching — and that might be a little bit of his problem. I don’t think he has a trainer who’s taught him a lot. Natural fighter, natural talent, but doesn’t have a lot of great moves. He has four or five setups and Manny knows every one of them.”

Roach collected his seventh trainer-of-the-year award last week from the Boxing Writers Assn. of America.

“How can they give him that award when my son’s about to go kick his guy’s ass?” Mayweather Sr. said. “I don’t care if they give me a trophy or not. We coming to do something. We going to get the job done.”

Those close to the Mayweathers say the boxer seeks a victory against Pacquiao to underline not only his own talent, but his father’s.

“Floyd’s dad had him on the straight and narrow when we were kids, kept him away from what he was actually doing,” said Ricki Brazil, a childhood friend of Mayweather Jr. from Grand Rapids who now works for Mayweather Promotions.

“Floyd didn’t go that route because he’d seen so much bad stuff and stayed dedicated to boxing, because that kept him out of trouble. He loves his father. His dad taught him what he knows and Floyd perfected it. It makes him feel good that it was his father there at the beginning and at the end.”

Mayweather Sr. said father and son have solved the puzzle of how to beat Pacquiao.

“When we see what a guy’s doing, we know what to do … how to offset it,” Mayweather Sr. said. “Pacquiao’s jumping in, jumping out. When he jumps in one time … you know, don’t even worry about it. My son jumps on him, he’ll be out of there. … My son’s smarter than Pacquiao. Way smarter. This is a professional fighting a sub-novice.”

Mayweather Jr. is intent to let his bold, uncensored father and his own performance do the talking. After Pacquiao, Mayweather Jr. said he’ll fight once more, in September, and then retire.

“The world don’t have to say anything to my dad,” Mayweather Jr. said. “As long as my father knows I love him and that when I went out there, I didn’t just do it for myself — I did it for the both of us — I think he should be happy with that.

“One fight shouldn’t validate my father. What about his son being [unbeaten] for 18 years? That don’t validate him?”

lance.pugmire@latimes.com

Twitter: @latimespugmire