Engine Primer Line
 

I found a chafed fuel line to the engine primers below the throttle quadrant on my O-2 this morning.
The part number on the line is 1500106-151, and supplies fuel pressure to the two engine primers on the quadrant.
Had this line chafed thru, fuel under pressure would have flowed into the cabin at the base of the quadrant. The only way to shut off this flow would be to close the front engine selector valve, and shutting down the front engine.
Please check your lines for chafing at your next opportunity.

What was coming into contact with the lines or what were the lines rubbing against?

The throttle and prop control cables.