Controllking servo issue

[fishmasterinvt]

I have a Controllking remote throttle system attached to a 4 stroke 8hp Merc. and it works great when it works, but the servos keep failing. They seem to overheat and act erratically. I bought the unit used, but ordered the correct install kit and everything is hooked up according to the instructions I received with the kit. I was wondering if anyone else has had these issues and how it was resolved. Maybe a heavy duty servo? I emailed the manufacturer and am waiting for a response. I don't give up easily, but I've lost some nice fishing days due to this headache.
Any help will be appreciated.