Also a supplier used non-stainless steel nuts on a number of the valve bodies which rusted and deteriorated the polymer material over time, loosening up the end caps and allowing water to leak past the o-ring seals.
The pressure relief valves have since been improved and in addition, withstand higher pressures.
Inspect the flywheel and stator for any corrosion, lift up the rubber boot and check the big blue capacitor terminals, and be sure the throttle shaft and linkage move freely.
"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.