Need assistance identifying this cable

[The_Dude_Abides]

Ok, so this is a 2006 Mercruiser 3.0L TKS with an Alpha 1 Gen 2 outdrive.

So I finally found where water was leaking into my bilge. There is a hole in a cable (further down) that is leaking water into my bilge (i.e., the cable is filled with water - it leaks because it looks like the cable was resting on the exhaust and partially melted through leaving a pinhole - nothing appears to be leaking from the connection to the hull). The cable connection through the hull is circled in red and the cable joins a wire bundle that looks like it goes to the helm. I need help identifying it and any suggestions for why it is filled with water (I don't think it should be!). It leaks more in gear and moving and slowly stops leaking when put in neutral. My best guess from my internet sleuthing and my review my mercruiser service manual is that its the speedometer cable.

Any help is appreciated

Thanks Justin

 

[Bt Doctur]

guessing its the speedometer water pressure feed

 

[Bt Doctur]

 

[achris]

... and the cable joins a wire bundle that looks like it goes to the helm. ... and any suggestions for why it is filled with water (I don't think it should be!)....

It's not a cable, it's a tube, and it's supposed to be filled with water. The speedo works on water pressure. That tube is connected to a small hole at the front of the drive. As you move forward, the water pressure increases, pushing the speedo needle further up...

Chris.......

 

[GA_Boater]

It shouldn't be filled with water. The water pressure from the small hole in the leading edge of the drive pressurizes the air in the tube. The pressurized air is what moves the speedo needle. If water reaches the speedo, it's ruined.

The only ways for water to fill the tube are a broken speedo or broken/leaky tube.

 

[achris]

It shouldn't be filled with water. The water pressure from the small hole in the leading edge of the drive pressurizes the air in the tube. The pressurized air is what moves the speedo needle. If water reaches the speedo, it's ruined.

The only ways for water to fill the tube are a broken speedo or broken/leaky tube.

Yes and no. The way the air in the tube is pressurized is by water being forced into the tube, so at least the first part of it will have water in it, while you're moving. In theory, when you stop, the compressed air in the tube should push all the water back out. It's called a bourden tube...

If you have a hole in the tube, then it will fill to that point, and no further, and not register anything on the speedo...

Chris........

 

[The_Dude_Abides]

Thanks all. My spedo works ok at high speeds, but less so at low speeds(it doesn't register until we hit about 20 mph and then it's decently accurate based upon GPS). Makes sense that I only see water spurting out when the boat is in gear and moving and why it stops when idling.

Is there a quick way to fix this without redoing the entire tube from the helm to the transom? I was thinking about cutting the damaged section out (1/4" at most) and then using a barbed vacuum line coupler to connect each end such as:
https://www.amazon.com/Disco-Automo...D=51%2BBkcUtN2L&preST=_SY300_QL70_&dpSrc=srch


thanks
Justin

 

[achris]

...Is there a quick way to fix this without redoing the entire tube from the helm to the transom? I was thinking about cutting the damaged section out (1/4" at most) and then using a barbed vacuum line coupler to connect each end such as:
https://www.amazon.com/Disco-Automo...D=51%2BBkcUtN2L&preST=_SY300_QL70_&dpSrc=srch...

That will do just fine.

 

[The_Dude_Abides]

Just to update this thread and close this in case others have this problem. It was the spedo hose and I successfully patched the cable with a vacuum line coupler. I believe it was 1/8"

I used some silicone to help slip the tube ends over the adapter, then ziplined it tight. No leaks and the spedo works better than ever!

Thanks for everyone's help!