Excess semen when ejaculating, should I be concerned?

No. No. The volume of ejaculated semen widely varies among men because all men are born with their unique size of seminal vesicles resulting in different semen storage capacity and not suggesting male's power or fertility. So, don't worry.
"?" Not sure what you mean by "excessive;" most men ejaculate between 2-to-5 mls of semen at each encounter.