Need to get someone experienced on the boat. Frankly, it's not even clear that there is another wrong with the steering. It may just be that boat steering is heavier than the OP expected, but is perfectly normal for such a boat and system.
So far, all we have done is go in circles because we don't know what's there, we don't know what works and what doesn't, and we don't even know if performance is abnormal or not. All we know is that it's not what the OP expected, but it also doesn't sound like he has any baseline to know what to expect.
Maybe there is something broken. Maybe the OP needs to adjust expectations or spring for power steering.