73 Evinrude backfires

[Deltho14]

I have a 73 Evinrude 50hp. When i try to start it every 4 or 5 cranks it backfires one time. I put new coils, new power pack, rebuilt the carbs. Did a compression check and both cyl are holding good compression. Pulled the flywheel replaced the key. Pulled and cleaned the reeds. Adjusted the timing. Still the same thing every few cranks it just back fires one time really loud. It has good spark. It has something to do with the fuel entering the cyl.

[Elton Smith]

I had one do that.It sheared the woodruff key but not all the way and cored the flywheel out.Would not run after that.Check your flywheel.I think the coils were rubbing.