"Bobby.... The size of the pro
"Bobby.... The size of the prop shaft on your engine is something we wouldn't know as there are two different lower units that will fit that engine.... the standard or electric shift type 75hp lower unit whereas the gearcase does not split at the propshaft center line.... and the heavy duty gearcase which does split at the propshaft center line, having the skeg attached with a number of screws (same type gearcase as the 1958/59 V/4 50hp models).
In either case, explaining what you have would be sufficent to anyone that might have the test prop you're atempting to locate. There would be nothing that we could add except the part number as listed below. Original part numbers followed by superceeded numbers:
75hp Std type gearcase P/S - 377869 - 380803
75hp Elec type gearcase P/S - 378518
50hp type Hvy/Duty gearcase P/S - 305407 -311062
The weak spark problem could be contributed to a weak coil, failing rotor, shorted condenser, something you'll just need to check into. If you find you need a coil, let me know.
I'll need to know if you have "Magneto" ignition or "Automotive Type" ignition.
Joe
"