I have 2015 E-tec 150 on my 22ft Sylvan Mirage pontoon that was put on the water last August and ran through October and then back on the water in April of this year. Over the weekend, after running it at all speeds and pulling tubes for several hours, it suddenly developed a "chatter" that seems to be coming from the lower unit. The chatter can be felt and heard at all speeds other than neutral or reverse. Suggestions?
A chatter or any type of metallic noise coming from the motor is not a good thing.
Because we cannot hear or diagnose your motor using a keyboard and a monitor, please have your dealer check it out. Often an unusual noise is from something else resonating through the boat hull which sounds like a motor problem. It is best to have it looked at as soon as you can to be on the safe side.
"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.