speedo tube is clogged

[TBarCYa]

I believe my speedo tube is clogged because it's reading 30mph and the boat is on the trailer. I have a compressor and would like to blow air backwards thru the system to force the crud out of the tube. Can anyone point me to the best location to get to the tube for this? I can pretty easily pull the tube from the gage but then I'll be pressurizing the whole tube and taking a chance of butsting it. I'd rather go to somewhere in the engine compartment where it's a much shorter run.

Any help would be great. Thanks!

[Brit Rider]

as far as I know... the run of cable goes like this:

-Back of the gauge (with a barbed pressure fitting and zip-tie)
-Along the gunnel on the starboard side
- Into the alpha drive from inside the boat
- out of the drive at the front of the leg, just above the cavitation plate.
- into the pick up.

If you trim up your drive you should be able to see the rubber hose, simply pull it off the pick-up. Then remove the pipe from the back of the gauge and blow thru it (from the gauge to the pick-up end) with the compressor to clear an gunk.

I'd actually check the pick up first though as this is more likely to be where any crud has gotten in.

Also, when you remove the tube from the gauge, ensure it drops to zero instantly, if it stays at 30MPH, it's the gauge that is bad, not the pick-up/tube. As a simply (yet highly entertaining) way of testing the gauge do the following.

Remove the gauge from the dash, call a helper, and then get them to blow as hard as they can into the back of the gauge (as if they were blowing a baloon up). When they do this you should be able to see the gauge go up and down. 8)

Mike

[TBarCYa]

The only helper I have around here is the girlfriend and getting her to... Aaah nevermind. :-)

When I pulled the tube from the leg, the pressure released instantly and the gage now reads zero. I took a single strand from a 10-6 electrical cable (I'd guess 3/32" diameter) and it wouldn't go in the hole in the leg. Either there's something seriously stuck in the hole or the wire is too big. A little later this morning I'll start up the compressor and see if I can get the blowgun onto the fitting on the leg and hopefully blow the crap out of it.

From the fitting on the leg (where I removed the tube) to the hole, is it plastic tubing inside or cast into the housing? If it's plastic tube, I don't want to put too much pressure into it.

Thanks.

[seapuppy]

Tbarcya
welcome to the zoo...for your speedo...this is what usually happens..sometime or another, someone hit something and part of it is logged in the speedo or the peto hole....look just about the torpedo part of the drive..there should be a hole on the leading edge of the outdrive.....take a 1/4 in drill bit and work it into the hole ...you should find either wood buts or muck....if that's not it..then you need to drop the lower half of the leg and clean out the cavity where the peto hole is...it's just a chamber and can get mucked up if someone drove the boat into the sand or bottom.....there is a reducer where the rubber tube attaches too.....
hope this helps....


SP

[TBarCYa]

I'll see what I can do. I have to guess that it's a piece of wood because the wire I was pushing in didn't go very far at all and it's much smaller than 1/4".

I'm not going to drop the leg just for the speedo so if I can't dig it out with something stiffer than the wire or compressed air, it will have to wait until the impeller needs to be changed.

This boat is brand new so if anyone hit anything it would have been me. I know there was a lot of wood in the water that day (and the day before) so it's very likely there's a piece of wood stuck in there although it seemed like I may have gotten the drive in the mud as well.

My boating season is on pause for 10 days while I'm out of town so I will mess with it when I get back.

Thanks.