Timing a 4 hp, 2 stroke Merc

[Border Waters]

I have a '76(?) 4hp, 2 stroke Merc that has fuel, spark and compression. While turning it over (drill on flywheel) I only seldom get a POP. I'm led to believe that the timing is way off. Where do I start in getting this timed? Can I use a timing light? How many degrees from TDC should I be setting it?
​Thanks for any help here.

 

[Sea Rider]

On newer 4 HP Merc engines exciter and pulser coils are fixed, nothing to adjust, don't know on 76 model.

Happy Boating

 

[racerone]

Check the flywheel key.