That should be enough mah, I prefer higher only because of the lower voltage. The higher the voltage the lower the mah can be to get similar run times.  Have you put a battery checker on it after it quits? I have one from the LHS that loads the pack with 300 mah and reports back capacity.  One other suggestion, and I did this myself, cycle the pack a few times if you have a charger that can do it automatically. It increased the run time of the pack.