Leaking fuel from overflow.
 

Hi all,
Since my last ride my 2013 EC300 has been leaking fuel from the carb overflow pipe. I was ready to remove the carb to give it a clean (or order parts if required) but noticed the hose in the attached photo was damaged. It goes from one port on the side of the carb directly to another port on the opposite side of the carb. I dont believe it is a breather as it doesnt vent to air.

So two questions:

1. Can anyone tell me what the purpose of this hose is.
2. Would this hose being damaged cause the carb to leak fuel out the overflow?

Thanks all in advance.

Regards,
Ryan

Usually it's not hooked up like that. A separate hose would come off each barb and run upwards on the frame. Alternately they could be tee'd into a single hose that goes upward to vent.

I doubt hooking them together is an issue, but the float bowl does need venting so fuel will enter. You are only venting the float bowl, so all the connections are doing the same thing. Mine is teed to a single tube that goes to the top of the airbox.

Fuel out the overflow is from a float level set too high or a float needle stuck open. Sometimes you can rap on the float bowl with a screwdriver handle and get the float needle to seat.

chain looks like its seen some miles too

Had the bike been sitting for a while with ethanol gas in it?

Needle valves do just go bad. I would pull it apart and give it a quick cleaning and check the float height, and change if necessary, and inspect the needle carefully and replace if needed.

If that doesn't fix it you you can try polishing the valve seat as they can get rough over time. I've had to do it before and saved me from pulling my hair out wondering why it kept leaking. Here's a vid showing how to do it... https://youtu.be/zlez_hdoWYk