90 hp Evinrude etech alternator problems

by Alex
(Grand Rapids MI)

Went out fishing on Erie Saturday only to get stranded halfway through the day because my starter battery was dead I jumped it and got it running and kept it running all day I then got the battery load tested and it is fine. I have hooked up my testers and found that the voltage stays the same with the motor running or not running that would mean I have a bad alternator/ power pack correct?