Does Battery Voltage affect RC Boat Power?Does mAh matter?

I have an APACHE 24 RC (PRO Boat)- it currently uses a Ni-MH 7.2 3300mAh battery, can i use something thats the same Voltage but more mAh, such as 5000mAh, will it burn my motor or the other servos? And Other way around (Same mAh but more Voltage)? Or nothing will affect (Volatge nor mAh) and i can use what ever i prefer?