u/PrestigiousPanda3659

I have this evinrude 20 hp outboard from 1989 that's been giving me trouble lately. It starts and idles fine, and works great even at higher throttle for about 5-30 minutes. But every time it runs it starts doing this pulsing at higher speeds after just a bit of runtime. It still runs fine at slow speeds, but increasing throttle causes it to pulse. (See video) I thought it was the fuel pump so I got an OEM repair kit for it, but no changes. I have made sure that there are no air bubbles in the fuel line, and I also disassembled the carburetor and cleaned it out. I'm starting to think it may be an ignition issue but I'm unsure. If anyone knows what might be the issue that would be super helpful! Thank you!