Re: Why does an Evinrude airbox cover have two holes plugged
The airbox cover should have all 4 holes plugged-that's normal. These engines should be run with the airbox on the engine-and my guess is with those 4 hole covers in place. The engine is jetted to run with the cover on and probably with those holes plugged. Removing the cover itself, or the 4 hole covers will increase airflow somewhat to the carbs. Increased airflow without extra fuel could create a lean condition for the engine. It will get plenty of air through the existing large duct on the back side of the rear half of the airbox. Having said that, most of these older crossflows ran fairly rich on the old leaded gas that existed when the engines were made. Proabably would not have been a problem years ago. Not sure just what the impact would be using today's 10% ethanol fuels with those covers removed.