Thread: What is this hose for?? 2019 115hp Mercury

2019 Tracker 175 WT deep vhull
2019 115hp Mercury outboard


Was cruising the other day around 4,500 RPMs and buddy turns around and says "what's that thing spewing water out?"

I turn around and see the tube in the picture has come loose from the silver coupling that's attaching it to another tube. I slowed down and he leaned back to reattach it and I asked him to verify if it was water or gas...it was water. The only "unusual" thing I had going on at the time is that I was running the manual bilge pump from a toggle switch on my dash board b/c it had rained the night before and I don't have an auto bilge on this boat. I asked him if me cutting off the bilge stopped the water and he said yes but I didn't see it myself before he had it reconnected onto the silver coupler.

It appears that the coupler is a "step down" coupling....connecting one hose that's wider to a smaller gauge hose.

I have no idea what this is for and why it would be carrying water through it. I did look at the outboard at the time and it was peeing water out of the back of the motor so I don't think this had anything to do with temperature......but I don't understand what connection this thing might have to a bilge pump....but he said when I turned the bilge off it stopped shooting water out of it.....but again, I didn't see it with my eyes, I'm not positive he understood what I was asking, and I don't understand what this small diameter tubing would have to do with a bilge pump.

Any ideas? I keep forgetting to look in my manual.

EDIT: The side that came loose was the side of the coupler that doesn't have the wire tie on it. I need to move that wire tire regardless.

Sliderman, thank you for the feedback. One other person had mentioned to me that they thought it might be related to the speedometer too......the water pressure gauge sounds like it's very feasible too.

Appreciate it!