Yamaha P115 1994 Speedo channel Clog Depth?

On a Pro-V 115 1993-1994 (2 stroke) can anyone out there with a functioning Speedo measure the exact depth of the little hole in the lower unit for me with a wire (the red part in the drawing)? I cleaned it it seems all the way back, no more sand aluminum corrosion is coming out, but still I can't get much air through it with the air compresor. I also ran a wire down from the top vetical channel and it passes the threaded nipple and keeps going but does not seem to quite reach the horizontal Speedo channel, but again, not a trace of corrosion coming up on the wire.

Today, I took the gear case off to change the impeller, and so had the opportunity to deal with the speedo clog from the top (the hose nipple) all the way to the intake hole in the gearcase.
The hose nipple is plastic, so I could not remove it. I took a welding wire like 1/16” and fashioned a drill and hammered the end like a flat head screw driver and gave it a point and drilled from the top down and horizontal at the intake hole in the front of the gear case. It took like 2 hours of work, and the compressor would not push the gunk out. I then put Ospho down the top with another 1/16” welding wire, it made a paste out of what was left and I had the keep drilling and taking it out and cleaning the wire every time and little by little the stoppage was removed till the compressor finally blew through. Then I put a straw and sprayed Isoprpyl Alcohol through it to clean it and then more compressed air. The job is done!
ANSWER TO MY QUESTION ON THIS THREAD: : the vertical depth from the tip of the hose nipple to where it hits bottom is 24.5cm . The horizontal depth of the gearcase intake hole is 3.4cm. (I was short by like 2 inches on the vertical hole the last time, and that was where the clog was.)

Use a gps,those speedos are unreliable and will clog again in notime ! Are you running in salt water?

johnnygjr said:

Use a gps,those speedos are unreliable and will clog again in notime ! Are you running in salt water?

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All True. Knowing what my speed is, is not really of importance to me, I just wanted the gauge to show something other than 00. (and I wanted to conquer the problem!)

I do not have a GPS, never needed it for where I went for 45 years saltwater fishing (South Florida), since I knew it like the back of my hand and GPS ruined my secret fishing spots by making them easy to find again by any novice that saw me there. People would actually drive right up to me and take the GPS coordinates!

However, now I have moved to Central Florida, and I'll be dead before the 45 years I need to have the same knowledge of the area, so sooner or later I will have to get GPS.

Thanks for the response.

I can sympathize with you,fished central jersey 45 years,sandy hook area,never had a speedo or gps,just a tach. and gas gauge

Klink said:

..... Then I put a straw and sprayed Isoprpyl Alcohol through it to clean it and then more compressed air. The job is done!.....

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For posterity sake, the repair worked for 5 minutes then got clogged again. I didn't bother with it anymore.

Klink said:

All True. Knowing what my speed is, is not really of importance to me, I just wanted the gauge to show something other than 00. (and I wanted to conquer the problem!)

I do not have a GPS, never needed it for where I went for 45 years saltwater fishing (South Florida), since I knew it like the back of my hand and GPS ruined my secret fishing spots by making them easy to find again by any novice that saw me there. People would actually drive right up to me and take the GPS coordinates!

However, now I have moved to Central Florida, and I'll be dead before the 45 years I need to have the same knowledge of the area, so sooner or later I will have to get GPS.

Thanks for the response.

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If you have a smart phone there are numerous free speedometer apps to choose from to download. The apps are as accurate as GPS speed, since the app uses the smart phones internal GPS.