I absolutely agree with checking the Speed Controller if you go with a hotter motor. Going with a fast motor with less windings also generates a lot of heat, and usually shorter run times. Keep in mind your prop also. Generally, you will want to go with a smaller prop and I believe a pretty good pitch. I prefer to run with the bigger motors and add batteries for speed with big props. I do have a CEN acqua jet I'm about to drop a Fantom 13 turn into. Anyone have any ideas on that?