Assuming that you can easily reach 3,600 in neutral, then you do have too much propeller. If you cannot easily reach 3,600 in neutral, first adjust the controls so that you can.
If the controls are correctly adjusted, then this could be because your propeller has a larger blade area ratio (BAR or EAR) that 50%.
I suggest that you get a propeller company to take 1" of pitch out of the prop which will help considerably.