Hello, E30 runs well except when trolling. It misses, stumbles and shakes. Fishing buddies even notice rough running. New plugs, yes indexed correctly. New computer software as of August 2018 during dealer visit, Fresh non-oxygenated fuel, set to XD100 oil injection.
I assume all inputs to fuel and air flow are electronically controlled? For example, no idle screws to adjust or blow out?
rough idling could be from a number of factors, from something as simple as a thermostat not warming up the motor enough to an ignition or fuel injector abnormality. Contact your dealer to have the motor diagnosed and checked over.
"There is never just one thing wrong with a boat";
-- Travis McGee, main character in a book series by John D. McDonald
The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.
The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.
Thank you for the self evident suggestion. As a retired development engineer for a consumer product, engine driven company, i expected no less, due to the poor engineering and develpment of this engine. I have since sold it and bought a Yamaha.