I just had my engine rebuilt by a mechanic.Im trying to get the engine started but it turns so slow and its not the starter. I tried a different starter already. Any ideas what I should do?

 

Most of the time when a engine is rebuilt, it's tighter inside than when it's been ran for a while. My guess is the
engine is tight, if it's a stick shift get it pushed off and start
it that way, after it runs and that would be for several days
or miles it will get loose and start correct. If it's a automatic
then go back to the mechanic and get him to start it. It
also could be( is this guy a mechanic) is something too tight?