94 P115 Speedo channel Clog Depth?

[KlinkSanford]

On a Pro-V 115 1993-1995 (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 vertical channel down 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.

[dave1939]

I have the same problem as you (see the speedometer plugged passage) thread. I used a 1/16th drill bit to clean out the horizontal passage, but it only goes in about 3/8ths of an inch. I need to start from the top as you did.

[boscoe99]

As small as the tubing is you are not going to get much air flow through the system. In fact, the system is not designed to flow air.

It works on pressure. Water impinging upon the pitot tube causes air pressure within the tubing to rise. The rise in air pressure acts upon the speedometer to display air pressure in the form of miles per hour, kilometers per hour, furlongs per fortnight or any other value for with the speedometer is designed.

The best that one can do is to run a 3/32nds drill bit into the pitot tube and turn it by hand to auger out any material that may be trapped in the tube. It will only go in about an inch or so. Then blow out any remaining debris by forcing air downward into the tube at the fitting that is screwed into the lower unit.

If you need to drill downward into the lower unit you will more than likely need a 12 inch drill bit to reach the turn point.

#18 x 12" HSS Aircraft Extension Drill Bit, Qualtech | DrillsandCutters.com

[TownsendsFJR1300]

Read this thread I made up awhile ago about keeping the pitot tube clear and the speedometer working 100%.

At the very least, do as I did, cut a "V" cut in an old washer machine hose and use your garden hose nozzle to blow water from the pitot tube upward. You'll know if its clear and it will flush crap out once water starts actually flowing..

Once clean, I regularly pressurize from the lower unit with that hose, the speedometer will read about 17mph and then that built up pressure blows back out the hole showing its nice and clear... I use the Air compressor to blow ALL water that accumulates in the hose under the deck...

http://www.yamahaoutboardparts.com/f...g-th23159.html

[KlinkSanford]

Will try the v hose trick.

I just measured my horizontal speedo hole depth and it is 1/16" shy of 1.5", better know as 1 7/16".

[TownsendsFJR1300]

Will try the v hose trick.

I just measured my horizontal speedo hole depth and it is 1/16" shy of 1.5", better know as 1 7/16".

Hold it tight to the lower unit and lots of on/off squirts with the nozzle trigger.
The higher the pressure the better.

If you can sneak a little bit of vinegar down from the top with a syringe and let it soak, even better..

As noted previously, HAND SPINNING a small drill bit CAREFULLY should help. Don't break it off in there or use a drill or you'll be posting here again and likely with no fixes...

Good luck and please post back..