Balance Tubes?

[levittownnick]

I have a 1997 Johnson Ocean Runner J150EXEUE that I have purchased new in 1997 (20 years ago) and I just discovered a factory defect. One of the Balance Tubes on the Port side that connects between Cylinder #2 and Cylinder #6 was pinched between the Starter Motor and the Fitting for Balance Tube Cylinder # 4. It was pinched so tight that it was completely closed-off and was difficult to force out of the pinch area. Of course I replaced the Tube but I would like to learn the function & theory of these tubes. I would appreciate he lesson.
Thank you,
Nick:happy: