"I did feel a bit rusty. I hadn't been in the ring for 10 months," Kara said.
"I did a bit of research on the guy (Sheck) and he is more of a boxer, so I decided to wack away at his legs to wear him down. The plan worked and I managed to win all three rounds."
Kara appeared to have total control throughout the bout and that was reflected in the unanimous decision going his way.
"I hope to get another fight in before the title fight, but if I don't I'll just have to wear it.
"Tuitupo is big. He's 6ft 9in (2.04m) and weighs in around 150kg. I'm not that tall and my fighting weight is 110kg. Super heavyweight is 95kg and over.
"I'll be doing a lot of training before September, but I really need to thank my trainer Lee Ashford and boxing coach Ivan Lacy as well as all my sponsors and supporters for helping me get this far," Kara said.
The title fight is in Hamilton on the Battle in the Waikato Round 9 card in September.