If you happen to need backup, spare parts I have an OPS 65 gold head an OPS 67 (BOTH ABOVE ARE INTERCHANGABLE) Both are well used but are decent for parts. $75.00 each, if you take both I'll pickup the shipping.
Inboard engine, standard rotation is counter clock wise looking at the prop.
What you are discribing, sounds like rotor disc, to crank pin is 180* out.
The rotor on OPS engines have 2 slots that the crank pin can engage
Sounds like it was assembled incorrectly.
Plug the stinger end with a dowel, wrap with electrical tape, cap off the pressure fitting, fill completely with water plug the inlet and place in the freezer and watch closely. If left too long, it WILL split the pipe.