Question about speedo "V" notch in the leading edge of the lower unit.

[vetplus40]

I have a plug in the speedo line that I have not been able to unplug with conventional methods. I am trying to get a "visual" on what is behind the "V" notch inside of the lower unit. Is it some type of aluminum tubing - machined in the drive itself - with a 90 degree bend that runs up to the quick connect plug that you can disconnect to blow our plugs (at the end of the rubber tubing, or is it some other design? I have looked at a few exploded drawings and cannot see exactly what I am looking for. I apologize if my request is a bit confusing, but it is a bit hard to articulate exactly what I am asking for. Thanks for any help.

 

[achris]

Ok, trying to remove the plug in the end of the line so you can hook up a speedometer... If you have enough excess, why not just cut it off? You'll only lose about an 1". Not sure you'd be able to blow it off.

The structure is the notch is part of the casting, and at the top of the casting is a threaded fitting. That fitting connects to the line that ends up at the end of the hose you're trying to remove the plug from...

HTH,

Chris........

 

[harringtondav]

The 'V' notch is connected through a drilled passage that goes up to the speedo hose connector pipe tap port in the top of the lower prop hsg. I boat in the trashy Mississippi river, so wood plugs in this notch are common. I use a 1/16" drill on my cordless drill to remove these...most of the time. The effort to remove the plug material won't cause you to drill deep enough to cause any damage. But caution. If you twist off the drill you've got real problems. I rigged up a back flush hose using a female garden hose connector, barbed fitting to plastic tubing that accepts the Merc. speedo tube connector. Tightly wire tie the Merc. connector to the plastic tubing. Connect this rig to your garden hose and the housing fitting, and crack the hose bib valve. It will work up to your supply's full pressure. If the plug doesn't flush out, work it with the drill bit until it starts weeping. Then wait. It will eventually flush out.

 

[vetplus40]

Is the line inside of the lower unit some type of aluminum or stainless steel? Does this line make a 90 degree turn up, or does the line simply attach to a fitting that is part of the "V" notch? I don't want to drill deep enough that I drill through the back of a piece of tubing making a 90 degree bend or the back of some type of fitting.

 

[harringtondav]

Is the line inside of the lower unit some type of aluminum or stainless steel? Does this line make a 90 degree turn up, or does the line simply attach to a fitting that is part of the "V" notch? I don't want to drill deep enough that I drill through the back of a piece of tubing making a 90 degree bend or the back of some type of fitting.

In an Alpha Gen II the V notch in the front of the lower housing is machined. There is a small drilled passage that goes from the notch a short distance rearward. This passage connects with a larger drilled passage that goes upward to the top of the lower housing. At the top of this passage is a female pipe thread which has a plastic coupler. This coupler connects with a mating coupler on the plastic speedo hose that comes down from the transom. If these couplers become disconnected, no speedometer. If the notch gets plugged, no speedometer.

 

[achris]

Is the line inside of the lower unit some type of aluminum or stainless steel?

Neither. It's a just a drilled passage through the casting..