Goku couldn't beat Fat Boo?

[Future Warrior]

I've seen someone argue that Goku in fact couldn't beat Fat Boo even if he wanted to. Even though Goku said he could, that was before he found out that he can't charge his ki all the way up without completely draining him of his power in a living body.

 

[Captain Cadaver]

The only way to argue against what he outright tells us he can do is maybe taking into account it might be difficult to completely cover Boo with a full power attack. He later showed an inability to do so against Pure Boo even during the early part of their fight, after all, plus he may have been factoring in Boo's adaptability. He was still limited when it came to time, so defeating Boo in that time limit would still be a challenge.

 

[Future Warrior]

He also thought he could have beaten Pure Boo...

 

[Let's Go Fearless!]

He had a power to do it but not stamina and time wise.