Did you take Pics if the ignition’s wiring before recent work. I would suspect the ignition wiring if you d/n feel solid on it being wired correct.
Is it a plain Magneto Sys with the coil, points and condensers under the flywheel? If so, you should be able to start it fairly easy w/o the switch to know it is not wired correct.
I have a 70 35hp Chrysler with Mag Sys that is the same as some 55hp except for piston and etc to give it the 55hp power. I can pull start my 35 with a rope on the flywheel if it is not killed with the switch. Do you have a manual to show what color wires go where on the switch? Is the wiring diagram on the side of your motor showing what color wires represent what?
My 35 is electric start but I can jump the solenoid with the switch off to not kill the mag’s fire and jump start w/o the switch. I hope this helps in your troubleshooting. Plus, I feel others will help you if you h/n figured it out. A good close Pic of your switch as it is wired will be very helpful and Pic of wiring diagram on side of the motor. Most of all, ID what color wires are connected to what pole markings on the switch and what color wires = what on the side of the motor.