1989 Evinrude 90HP Inconsistent RPM

[Guardian29]

I have a 1989 2-Stroke 90hp Evinrude outboard on a 21' pontoon. I have the engine services over the winter and was told one of the cylinders wasn't firing. When I run the engine WOT at about 45000 RPM it will surge like I have more throttle. It will run steady for a bit and then surge up for a second a few times. It doesn't ever drop expect for a few times the engine has just stopped. I can turn the key over and it will start right back up and take off. The VRO was disconnected before I purchased the motor so I mix the oil with the gas. Does anyone have any ideas? Thanks!

 

[racerone]

Post your compression test numbers on this engine.------They are world famous for broken piston rings.-----?--45000 RPM sounds like it is a special motor.----Just kidding ------.Run with a timing light one cylinder at a time to see how spark behaves when it surges.