To answer your questions. Yes, you can use more than one type or brand of servo on the same receiver. A new servo probably won't fix your problem with the throttle. The direction the servo needs to move will be defined by the direction the throttle arm on the carburator moves to open or close. The transmitter most likely has a switch to change the direction of movement. If you have a manual, there should be a section explaining how to do this. It sounds as if the problem has to do with the throttle not opening fully and this needs to be addressed by adjusting the linkages or installing a longer servo arm so that there is sufficient travel of the servo arm to fully open the throttle. A new servo probably won't help you here. I don't want to sound condescending, but some experienced help would be very beneficial in getting the heli setup correctly and flying. Nearly every successful heli pilot has had help from someone else at some point in their career, and particularly when first starting out can save you endless time and money. Beware that there are 10 bench/keyboard experts for every one that truly knows what they are doing. Look for someone who flies well and whose heli is in good condition, then ask that person for help. I don't know anyone specifically in your area, but there are many heli pilots in SW Florida, and it shouldn't be impossible to find someone who can help you get it off the ground. Good luck. Steve.