1980 Evinrude 2hp start problem

I know there have been a number of issues like this discussed in past but I'm stumped. I have owned many of these & took this one as a project to learn more but need some second opinions please.
Here's the basic facts: Motor will not start & fires only occasionally (on 5th pull) for 2 seconds & only with a bit of gas sprayed in plug hole. I have tried to isolate the obvious issues to narrow it down. At first I though fuel issue & carb was disassembled & cleaned. Also the tank, fuel line & filter. But since minimal to no fire with gas sprayed in plug hole, suspected electrical.
- Coil primary winding seems to check good on the meter. / no visible cracks or damage to coil
- Secondary winding at the spike about 400 & 400 at the plug wire end ( digital Fluke meter) / unexplained using analogue meter shows 280 at plug end.
- Plug wire cut back 1/3 inch for fresh copper at the spike
- Point set at .020 (as best as I can )
- Spark tester shows there is spark at the plug / I think this should indicate a good coil & point ? spark intensity unable to determine
- New #1 gas & 50/1 mix
---- Just the odd "cough" (that kind that gives you hope) but no actual start:
All ideas/comments appreciated / Thanks

Will the spark jump a 1/4" open air gap on a spark tester ??

Start with a compression test,Next an open airgap spark test, You should get a lightning blue snap

Thanks to both of you. I have done compression tests today & get consistent 70 PSI. ( not sure what is acceptable). The spark test from 1/4 - 1/3 inch results in a snappy yellow spark . I do not see evidence of blue , but the yellow spark appears quite good to me.
Your thoughts please .

Try the spark test at night, Yellow will not cut it at higher rpm and under a load

Pull the head and inspect the cylinder wall for crosshatching? If it looks good get a new head gasket and slowly pull it down to spec. Does the points plate wiggle up and down? Just a little wobble will throw the timing way off it must be tight and move smooth. You can adjust the points with a timing light. Put a spark gap tester on the plug wire and pull the plug. Then spin the flywheel by hand and shine the light at the two marks on the points plate. The single line on the flywheel must be inbetween the two marks on the plate. I just tighten the flywheel nut by hand so its easy to pull the flywheel and adjust the points. Once your sure the timing is right be sure and torque the flywheel nut before you fire it up.

Thanks / appreciated ! I did do the spark test in a dark area but will test again. What would a yellow spark tend to indicate? (weak coil etc or point set-up?)
kimcrwbrt , will try your suggestion over next couple of days. Thanks to all , I am learning lots. I missed mentioning that I already have 2 other good working similar motors that , if necessary , I could switch over a part here & there to try.