Well had a hunch about fuel but that kills it. Total ignition shutdown means most likely before coils and you have replaced everything else so one would point to the stator. Heating up and shutting down.
Now you know how to test so hopefully it pans out.
Probably need to get the plastic part out or could cause problems. Here is the link to the eBay picture I sent in post #4 but that was from a 68 or a 69 55 HP that was previously suggested.
https://www.ebay.com/itm/133666791408
Maybe you broke the plastic part off when you removed it.
I would wait for guidance from someone who has worked on these because maybe you have to pull everything out to access it.
I have never worked on one of these.
Read this thread entirely. I believe it's the same problem you have and how people have corrected it
https://www.yamahaoutboardparts.com/forum/general-discussion/yamaha-outboard-forum/14826-1988-yamaha-200-etxg-outboard-oil-leak-in-cowling
I rinse with "salt away" but once your plugged i doubt it will work. There is also a product called Barnacle buster.
Lots of online stuff about testing rectifier and stator with a multimeter.
Funny, this is the commercial model year list on iboats yet doesn't list your motor. They must have a bigger list.
https://www.iboats.com/shop/basics/johnson-evinrude-commercial
77 series control box and parts breakdown.
https://www.marineengine.com/parts/johnson-evinrude-accessories/index.php?year=1992&model=Remote+Controls+1992§ion=Remote+Control&yid=34080&mid=34086&sid=38507
I take it you have a parts motor. Take a look how they plumb the primer...is their one tube to the carb and one to the intake? You might have to pull the intake too.
