I have a new-to-me 1996 Johnson 70hp. Runs a bit rough at idle so I changed the plugs which helped a bit. I figured I may as well try Evinrude Johnson Engine Tuner as well. The engine manual says to attach the engine tuner can to the Schroeder valve on the primer solenoid and follow the directions on the can. However the can says to spray directly into the carbs. Which method should I use? I purchased the adapter hose so I can use either method. Is one method more effective than the other? The Solenoid valve seems easiest but is it the best? Same situation for the fogging oil , when it is time for that at the end of season. Thanks for any thoughts.