Are the magneto`s / flywheel on a 5hp engine interchangeable with the 3.5 hp engine?

My 5hp engine (131232 - 0111-02 - 800 82307) does not spark the spark plug but I can feel a current if I hold the lead and pull the starter. I have replaced the points and the condenser and checked the gap on the flywheel. I have a 3.5 hp engine that produces good spark.

I noted that the earth wire from the magneto had no insulation on it?