You will be fine.
I am about 250, and had no problem with Journey to Atlantis, which I think is SW's best ride. I rode in many times in a row. Next to it is Krakken, a roller coaster, which I would not ride because it loops you, so I did not even attempt that ride. So I cannot help with Krakken.
There is also a simulator ride, Wild Artic, which I went on the motionless version - sitting in a theater, which is fine with me. Wild Artic is actually a very cool attraction. After the simulator part, you get into the animal area and it is very neat.
There is a kid area, but my wife rode with the kids on the rides. I sat underneath this huge play area. So if you have kids, I cannot help you with those rides, but the rides are set up for kids to ride alone with no problem.
Then you have the shows and animal attractions - which are great.
What you have to remember is the heat. It does wear you out. We have only been there once (two days in a row), but it was in August - Very Hot. We are going again this December, which I am looking forward to.
Sea World Orlando is a wonderful park. For us who are heavy, the only thing that may not work is Krakken.
