1996 evinrude 48 spl #e48esledc having problems.at about 1/3 throttle engine starts shuttering ,seem like only does it with more than 2 or three people in the boat, today i un plugged the heat sensor in top upper cyl, run in a barrel, but still don't know what it will do with a load on it. also has a rough idle. carbs have only one adj, screw, are they low or high adj, screws? thanks
