If you must water dip, use a slave motor to drive the new motor (run the slave backwards to drive the new motor in the correct direction). DO NOT lube or use comm drops on the new motor before water dipping. Run it at 4 volts (should pull about 5-6 amps) for 2 minutes and check- it should be pretty close. Only run it until the brushes are JUST straight up and down.
Then lube and use comm drops (we like VooDoo drops) and run at 7.2 volts for 6 to 8 minutes (directly, not with a slave motor). It should be somewhere around 13-13,500RPM @ 5 volts, or 19K + @ 7.2 volts.