Just went through this with my new motor in the spring. It seemed the more initial I gave it the more it wanted (MSD).Finally locked it out at 36 and it was good except for hot starts. A friend suggested removing just one of the springs so it was retarded while starting and is all in at idle. Has worked gat all summer and is easy to check timing and no problems with hot starts. No retard box needed, no hacking into wiring and free to try!