Speedo repair?

[David_L6]

Who/can a speedo be repaired/recalibrated? Mine reads too fast (I wish what it reads were true!). A C mod will peg it so a 44 is out of the question. I have tried a GPS, but I like the speedo for testing because I can read it while underway. All I can get from a GPS is top speed once I get back to the pits.

[modFE]

Hey, Sam 4-E had rigged up a good quality pressure gage and the painted the speed on the glass face.. I think.. maybe Sam could enlighten us on the deal..

[sam]

I use the same formula

69 psi = 69 mph .... wonder why that one is easy to remember?

Gages made for air conditioning and refrigeration work are very accurate (they have to be) larger steam boiler type gages are usually less accurate

David, if you send it to me I will try to calibrate it for you, I owe you a favor anyway.

[G Stillwill]

David my GPS reads both top speed attained and present speed Im running both on the same screen I just Velcro it to the dash

[Bill Huson]

Pre-GPS days . . .

I used a Keller speedo which was accurate. Are Keller speedos o longer available?

My regular boat has two speedos, a standard pitot tube rig whichs reads right, and a paddle wheel thingy attached to my depth sounder transducer which reads about ten miles over ??? Maybe I'll go modern and get a GPS someday, but getting lost is a fun adventure!

[The MercKid]

Keller speedos were just pressure gages with a different face and the rubber mounting tang added, made by Marshalltown Gage in Marshalltown Iowa. I always thought they were something special until I opened one up and saw that it was simply a refaced standard pressure gage.

[Dick Tyndall]

Gps...........?

Which GPS are you using, George?

[39R]

FYI, Keller Manufacturing Company speedometers are still produced and calibrated per the original design specifications by the company owner; Allen Thorsen of Computerized Marine Products, new units are marketed through Steve Greaves of Portage Bay Systems, Inc. Contact information is posted in two locations on the home page of this web site. Contact Steve for calibration pricing.

The last time I was in Allen’s shop, he was still using original bourdon tube assemblies manufactured some 15 to 20 years ago. The bourdon tube is the curled chamber that stretches as pressure is applied to create the linear movement of the dial. The type and quality of the ones Allen uses are difficult to find today due to manufactures not producing such a quality part any longer in favor of greater profits. I’m sure you would not be disappointed if you get your old one repaired.

[Check-book]

Gps

I use a GPS strapped to my wrist which has large numbers so you can read it underway and also retains the highest speed.Also,with it on your wrist,some of the false readings because of vertical acceleration are "damped "out.Easy to see numbers for even an old guy.
Dave

[G Stillwill]

Dick I use a Cobra 500 GPS I got it off ebay brand new for 85.00 if I remeber right going to be 60 this month so memories fade quicker......lol