Well, that is an old problem for genesis. The boat is too narrow and once you put more power (torque or bigger prop) it will turn right.
It is happening above a certain speed (~50mph) and you can not do much to solve it.
Some people say that offsetting the rudder to the right will help. It didn't help in my case but you can try.
Another solution is to use small prop (`38 to 40mm) and increase revs to compensate, so more KV on the motor.
The best (and expensive) solution is actually to go dual drive with counter-rotating props. That will solve your problem.
Even then, keep in mind that the Genesis will be very fast but it will corner awfull (for the same original reason, too narrow).
I hope other users will chime in with other solution, that is my experience.
Regards