Re: Wizard "Western Auto"
The Wizard WH6 came out in 1956 and was essentially the same as the Mercury Mark 6. Some books show it as a 5hp, but the Mercury was rated at 5.9hp, so the Wizzie is probably closer to that.
Use Champion J6C plugs, gapped to .030". Highly recommended that you replace the waterpump impeller and inspect the ignition components. Parts and manuals can be gotten through oldmercs.com.