Re: 1968 18 hp evinrude

[Don]

Well, perhaps it is just running on one cylinder, the jerking you refer to might be the second cylinder kicking in for a second. When you advance the throttle, does the motor stall, or just keep running but low on power.
Have you tried new plugs? The spark should be able to jump a 1/4" gap while cranking. Sounds like the carb is clean, I’m glad you didn’t try to remove the jet without the tool…
Any way of posting a video of the engine running/misbehaving??