It's hard to tell what this line is without seeing it. If it was a gas line, then it would be leaking gas out of it, so I am inclined to think that it is a vent.
If you could send me a few pictures of this, I might be able to tell more about it.
Usually the engines not starting is related to either the carburetor or the ignition coils....in some way. Have you tested the spark since you installed the new coils? If you still do not have spark, then the problem is usually in one of the safety switches...usually the Seat switch. Make sure that all switches are operating correctly.
If the carburetor is not fully clean and was rebuilt with a complete carburetor kit (You usually must use a full kit to get these to work) then you actually may have an electronic fuel solenoid (located on the carburetor) that has gone bad or is not receiving electricity from the ignition switch. Check this also.
Let me know what you find and I will try to continue to help.
still nothing just keeps turning over. Now I am getting no spark at the plug. I am going to check to make sure a wire is not grounding something out.
If you have no spark, you should remove the engine cover and then remove the small wire from the ignition coil then check the spark again. If you have spark this way, then the problem is in the safety switches. If you do not have spark, then it is in the ignition coil.
Most of the time the safety switch that causes the most problem is the seat switch.