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View Full Version : Speedo Problem - How to Fix?



RedDog
05-11-2007, 03:58 PM
Well it wasn't the pickup or tube to the speedo as can be seen. The guage seems to be sealed. Is there a way to fix it?
Looks like I won't need masking tape for the AOTH "Honest Joe" run :(


http://www.donzi.net/forums/attachment.php?attachmentid=28899&stc=1&d=1178917021


http://www.donzi.net/forums/attachment.php?attachmentid=28900&stc=1&d=1178917021

glashole
05-11-2007, 04:01 PM
I/ve got one that only goes to 60 but you can have it if you wish

same size :)

RedDog
05-11-2007, 04:06 PM
I/ve got one that only goes to 60 but you can have it if you wish
same size :)

Thanks anyway, but I'm usually well on the upper side of that :wink: :wink: :wink: :wink:

Barry Eller
05-11-2007, 04:37 PM
I've seen those "Donzi" speedo's on e-bay before. I just checked and none were listed. Time to buy a new speedo, (not the bathing suit).:yes:

How are the Vols looking? Football season is just around the corner.

gcarter
05-11-2007, 07:21 PM
Just out of curiosity, did you try to pull a vacuum on it???
If that does nothing, then the bourdon tube drive gears are probably jammed.

techspecial
05-11-2007, 08:48 PM
This is what worked for me...
I very carefully drilled a hole in the side big enough for inspection.
Inside you'll find the Bourdon "C" tube attached to it's movement.
The movement is usually made of brass and oxidizes very easily.
I sprayed the crap out of it with WD-40 and let it soak overnight.
I reached in with a jewelers screwdriver and forced the movement
back and forth until it freed up. If you touch the return spring your
screwed. Then I took a tire pump and rigged it to the gauge.
It takes VERY LITTLE pressure to move it full scale.
Pumped it to move the needle back and forth a few times.
It's been good so far.
Or just throw it in the trash and get a new one!!!
This is from a nuclear instrument technician...
GOOD LUCK!!! INSTRUMENTATION IS FUN!!!

mrfixxall
05-11-2007, 10:11 PM
Here is the most simplest way to fixx it...http://www.livorsi.com/

Johntrip
05-12-2007, 01:16 AM
probably have debris in the tube..... go for a spin with the tube open and see if the pick up shoots water through if it does its prob the guage...

After mine stopped for the 5th or 6th time I donated it and bought the Livorsi gps speedometer 3-5/8 w/special bezel for the 4" opening. Passed on the antenna mod. and wired it to the gps. 270.00 including bezel

MOP
05-12-2007, 06:26 AM
They rarely break just get the innards frosted over and get stuck, at time the return spring quits which looks like what may have happened to your. I would slip the end of an anti freeze checker hose over the end and pump the heck out of it that way you get a push/pull action, if that don't free it try the WD40 trick if that don't work "Round File It"

Phil

f_inscreenname
05-12-2007, 08:04 AM
Those "air tube" speedo's are notoriously wrong. Even if it is set right they are never consistent throughout the dial.
Do yourself a favor and upgrade to something better or maybe replace it with a clock and use GPS.
:)

gcarter
05-12-2007, 08:35 PM
The Gaffrig (Livorsi) monster liquid filled speedo I put in the Minx was incredibly accurate. It was ALWAYS within 1-2MPH with the GPS, but that's the exception. They're obviously designed to be more accurate.

roadtrip se
05-12-2007, 10:37 PM
I've checked it against my handheld and it is always right on.
Sometimes, depressingly right on.

The attenna puck is mounted on the left side of the foot well and works fine.

I'll show you at the AOTH.

RedDog
05-13-2007, 08:04 AM
Thanks for the replies - I'll be looking at what everyone has at AOTH for solutions. I totally killed the one I have trying to fix it with some of the above suggestions. opps

I hate that I'll have to add a gauge that doesn't match. Replacing with a full matching set is not a priority at this time

RedDog
05-24-2007, 07:09 AM
I found an almost exact match to what I had. It even has the Donzi logo. The only difference is instead of the threaded brass studs for mounting it has short non-threaded plastic studs. These won't reach the "mounting collar thingy." Any ideas on how to mounts this guage? I'm leaning wrapping it with tape to build up the gauge diameter to closer to the hole size and then using a silicon adhesive.