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JimG
11-15-2011, 09:32 PM
I’m finally going to install my new-old HM gauge panel, and I need some help.

When I purchased my boat way back when, my then-original HM tach was inop. I installed Teleflex Heavy Duty gauges to replace the originals. I wired the tach like I’ve always done. Boat would not start, it would kick then immediately die. Someone on the Donzi board posted that the old tachs were wired strange, (the ignition ran through the tach maybe?) I don’t remember how I did it, but I rewired the tach to make it work.

Now I am wanting to install an old school panel. The main plug is exactly the same, (the only difference in the new panel is the lack of fuel gauge, I think it was for a 16. Im still looking for one to match…). I would like to be able to just plug it in, but I am a little worried about frying the pristine 45 year old tachometer…

I haven’t traced the wires out yet, but could someone explain how the originals were wired? I want to undo the “fix” I made to the wiring before I hook it up…

Thanks!!

Jim

mattyboy
11-16-2011, 08:48 AM
Jim,

there were a few wiring variations with the ammeter and the external volt reg not sure if that included the HM tach. I might have a diagram in all my stuff I'll check.

What are the lugs labeled on the tach? they usually are I,S and G

mattyboy
11-16-2011, 09:04 AM
this given to me by Gary S when i was working on my wiring

it shows a lead to the ign switch "I", a lead to ground "G" , a lead to the coil "S" and it also shows a lead to the light switch depending on the gauge some have a short pig tail directly to the bulb and the bulb picks up ground thru the gauge casing like stewart warner, or the gauge has an internal wire and a lug for the bulb like teleflex. hope that helps

penbroke
11-16-2011, 09:40 AM
You should find the info you need in this thread (http://www.donzi.net/forums/showthread.php?23684-Help-for-old-tachs.&highlight=wiring) or this one. (http://www.donzi.net/forums/showthread.php?1482-Wiring-Diagrams&highlight=wiring) Too bad some of the photos are missing...


Frank

JimG
11-16-2011, 09:10 PM
No lugs on the old tachs. Just 4 loomed wires coming out of the same hole, yellow blue green and white... My panel is a factory pre- wired unit, with a white eight lug plug that plugs into the wiring harness.

JimG
11-16-2011, 09:18 PM
Penbroke, thanks for the links! Thats what I was looking for!!

JimG
11-21-2011, 10:40 AM
Is there a special sender I have to use for the old gauges to work?

I plugged the panel in and started the engine… the 45 year old panel lives!! Lights work, tach works, switch works! Amazed!

The oil pressure gauge is not working. I have an 80psi Teleflex sender on there now, and I cannot get a reading. (I know the pressure and sender are good, plugged in the other gauge…)

Any ideas?

mattyboy
11-21-2011, 01:23 PM
the sender impedance needs to match the gauge, each mfg'r has their own range usually pretty close. most are 0-240 ohms

240 ohms = 0psi
0 ohms = gauge pegged on the high side usually around 30 ohms will be full gauge rating ie 80 psi on a 80 psi gauge (on stewart warner stuff)


have you verified the gauge? have you measured the sender?
not sure what the specs are on the old hm stuff . if your sender is a teleflex i would see if you can find a stewart warner sender and see if that makes a difference.

JimG
11-21-2011, 01:55 PM
I haven't measured anything but the voltage going into the gauge.

Is there a specific 80psi sender that HM used for this gauge panel? When I bought the boat, it had aftermarket (Teleflex I think) gauges. I'm assuming the sender is a Teleflex. Works great on the Teleflex Heavy Duty oil pressure gauge currently installed on the boat.

Thanks!!

mattyboy
11-21-2011, 02:12 PM
not sure who made the gauges or senders for holman moody.

to verifiy the sender with a meter in ohm reading, ground side of meter to engine block positive lead to sender terminal with the wire to the gauge off.
with no oil pressure reading should be 240 ohms, then start the motor and let pressure build then take the same reading , approx 100 ohm should read half way on gauge 40 psi on a 80 psi gauge

to test the gauge short the ground lead and the sender lead on the back of the gague with the ignition on, that should peg the meter on the high side . the other catch would be if the sender is for single or a dual gauge setup that can make a difference in senders output.

I would assume you're going to have an issue with the water temp as well.

JimG
11-21-2011, 02:23 PM
The gauges were made by Teleflex.

mattyboy
11-21-2011, 03:05 PM
I would test the gauge to see if it moves at all, verify voltage , polarity, ground and sender leads. then i would contact teleflex and see what senders were spec'd for their late 60 early 70's gauges.

you can id the sender you have there should be a code on the hex head of the sender( if it is teleflex)

silverghost
11-21-2011, 06:08 PM
Could it be that since this is a never installed NOS (New Old Stock) HM/Donzi gauge panel that the oil pressure gauge never worked when new; and that is why Donzi never used it ?
Or~
Since it was never used could the oil pressure gauge's needle movement lube have dried-up & the needle is now stuck ?

I would try putting full ground for a moment to the gauge's sender input as Matty suggested to see if the gauge is in fact good & to possibly jog a stuck needle movement loose.
The needle should then peg at full scale.
Just touch the full engine ground for an instant while watching that gauge needle to avoid a gauge burn-out.

If you indeed have the incorrect sender you still should get at least some readings on that oil pressure gauge other than near zero.

Check for a complete circuit on that molded-in harness plug also.
Some of these molded-in plugs are not that great and can give you a a bad connection.

I believe that these old Teleflex gauges used the same exact senders as the similar old vintage Stewart~Warner marine gauges.
In your case you need an 80 PSI sender which is basically a variable resistor rheostat in a sealed can connected to a pressure idicating bordon tube.
The sender needs a good screw in pipe engine ground to work correctly as it works as a one wire only connection to the engine's ground.
The oil pressure gauge itself is a simple voltmeter calibrated in PSI to read the sender's variable ground voltage signal from it's internal rheostat.

The temp gauge is basically a millivolt voltmeter that uses a self voltage generating thermocouple sender that varies out put voltage according to the engine's coolant temps..

Matty~
Great oil pressure sender ID chart you posted !

mattyboy
11-21-2011, 07:25 PM
Jim,

let me be clear I didn't say apply voltage to the sender lead i said apply a ground or short the sender lead to ground. if your grounds are truely bonded it would be like the sender sending 0 ohms which will peg the meter on the high side.

since your HD gauge works i would bet the older gauge works on a different range which would be outside of the newer more common range of 240-0 or the gauge is bad

your gauges are hard wired so an easy test would be to remove the sender lead at the sender and hold it to the block in a spot that is a good ground. with the ignition on the gauge should move and peg. what voltage do you have between the ign lead and ground at the gauge?

mattyboy
11-22-2011, 07:42 AM
~~sg nice edit~~

the gauge is a simple meter but not a volt meter it is an ohm meter that measures resistance in a defined scale. just has your old analog sweep dial meter or new digital multi meter which has an internal battery and two test leads .

the gauge(meter) has internal battery usually 12 volts on it's I ignition and G ground leads from the systems 12 volt battery then uses the ground and the S sender connections as test leads to measure the resistance between block ground and the changing resistance provided by the sender. so take your meter set it in the 10's ranges for ohms and try to measure a circuit outside that range either the gauge pin pegs usually a dead short ( 0 ohms) or it doesn't move at all, on a digital meter OL might be displayed. the newer gauges all look for a range of 0 to 240 ohms from the sender this setup is the same for the temp sender. if the range on the sender and the range on the gauge don't match but do overlap the needle may move and give a false reading , depending on where the ranges overlap the needle might not move at all.

Jim
your meter isn't working so these are the possible causes

the meter's internal battery is bad :
there is not the correct voltage on the I and G leads

the meter has a broken test lead: the S lead is open i doubt this cause the old meter worked so the lead and the sender work

the meter is in the wrong scale:
the sender is in one scale and the meter is looking for another making the needle not move

the meter is bad:


Jim I went thru the same on my 16 wanted to keep the holman moody stuff but couldn't find the senders my holman moody oil gauge with a teleflex sender barely read 10 psi at wot and zero at idle ,mechanically the psi were at 37 psi wot and 19 at idle. I gave up on on trying to go old school and put in gauges and senders that were matched.

good luck hope it works out for you.

mattyboy
11-22-2011, 09:02 AM
Jim,

here is a link to the teleflex tech manual look down on the bottom of the page under instruments you'll find troubleshooting for all the gauges. I know these are for the newer gauges not older ones and most mfg'rs now operated in the same range but they are a good foundation for troubleshooting gauges.

http://www.jamestowndistributors.com/userportal/document.do?docId=684&title=Teleflex+Technical+Reference+Manual%3A+Table +of+Contents

silverghost
11-22-2011, 12:34 PM
There is, and never was, ANY internal "Battery" inside these old oil pressure meters.

If you don't believe me~~~
Cut an old one open~
You will see no"internal battery".
Then get back to me.

Is IS a simple volt meter that measures voltage to the engine ground through the sender which is a rheostat type variable resistor which varies the voltage to ground to the engine block.

The oil pressure gauge is NOT an ohm meter ~~~
They are just a simple volt meter.

The fuel level gauges of the same era also work exactly the very same way.
They are also simple volt meters and the fuel tank sensor is also a rheostat variable resistor that is used to measure fuel level by changing voltage to ground.

mattyboy
11-22-2011, 02:11 PM
Sg. I never said there was an internal battery in the gauge I said like a multi meter has an internal battery the gauge has it's 12 volts so please re-read my post. Also please explain why if the gauge is a volt meter they give the operation ranges in ohms and not volts if the sender is generating voltage what are the associated voltage readings for the listed ohms readings? Take a volt meter and short the test leads then take an ohm meter and short the test leads and get back to me

JimG
11-22-2011, 02:42 PM
Matty & SG, thanks for all your help! I’m going to check the gauges and make sure they work.

I’d really like to use the gauges in this panel. If it turns out to be too much of a hassle, I’ll swap them for newer (vintage-style) gauges…


Jim

mattyboy
11-22-2011, 05:27 PM
Jim
Maybe this would help these are the original sw gauges from my hornet
Oil press gauge d306-g
Oil sender d353-z
There's a sender on eBay for 80 bucks now. maybe you can find the specs for this sender and see if they are different from the teleflex.

mattyboy
11-22-2011, 07:44 PM
another bench test on a teleflex hd gauge would be a trip to radio shack pick up a few resistors in the neighborhood of 240, 100 and 35 ohms . wire the I to a + side of a 12 volt dc battery and the G to ground to the - side then wire the resistor in between the G and the S sender lead and see what the needle does.

this might be a way to find the operating range of the HM gauges get a 10, 20, 300 and a 600 ohm and see if it reacts to them.

Gary S
11-22-2011, 08:30 PM
I know this is compairing apples to oranges but I have a Correct Craft with a Holman Moody,and hope this helps. When I got it in the 80's all the gauges were busted out but the oil,temp,amp and fuel were Teleflex.I don't remember what the speedo and tach were but a friend of mine has the same model about 27 boats newer with the original Teleflex speedo and tach. I still have the original oil sender from my boat and it has these markings on it- 353 Z 12-V 80 M9. My Holman Moody owners manual/parts book shows a Teleflex panel with tach,amp,oil and temp,it looks like when you got the engine you also were supplied with the gauges and wiring harness. I would assume that if yours are marked Holman Moody they are in fact Teleflex. A call to Holman Moody would confirm. Lee Holman who is the son of one of the founders still runs the company and has at times even answered the phone. As I understand he was the force behind the marine division.

JimG
11-22-2011, 11:00 PM
Thanks for the part number! I'll look for one...

My gauges are clearly marked Teleflex, and the original box it came in is also clearly marked Teleflex.

silverghost
11-22-2011, 11:00 PM
Bench Test~

I just did a bench test using the exact old Teleflex oil pressure gauge mentioned here in my old 1972 Donzi 18 gauge panel.

I hooked 12 Volt Positive + directly to the left rear gauge terminal as seen from gauge face front.

Gauge case itself remained completely unconnected.

On the right hand gauge terminal I connected an EICO RTMA Resistance Substitution Box Model 1100
This lab resistance box took the place of the engine oil pressure sender rheostat variable resistor.
This allowed me to switch negative -ground resistance quickly just like the oil pressure sender does when screwed into the engine block oil gallery ground.

The other output side of this resistance test box was connected to 12 Volt Negative - power ground .

The oil pressure gauge was then connected as a simple DC Voltmeter as I described earler.

Here are my gauge readings & results.
Note: The old gauge's terminals were quite dirty & rusty.
I quickly cleaned them as best as possibe for this bench test.

Gauge & PSI Readings
15 ohms~~~Meter pegged over 80PSI
22 ohms~~~ 80 PSI
33 ohms~~~ 75 PSI
47 ohms~~~ 60 PSI
68 ohms~~~ 30 PSI
100 ohms~~~ 20 PSI
150 ohms~~~ 10 PSI
220 ohms~~~ 0 PSI

The gauge's needle moved very slowly during the switch from one resistor value to the next.
30 seconds between readings to get a stable reading.

This should give us all a good clue as to the original Teleflex sender's normal resistance operating range.

All readings were are not exactly precise~~~ but very close rounded up/down guesstimated readings!

mattyboy
11-23-2011, 09:08 AM
[ QUOTE=$originalposter]silverghost
Teleflex Oil Pressure Gauge Bench Test
Bench Test~

I just did a bench test using the exact old Teleflex oil pressure gauge mentioned here in my old 1972 Donzi 18 gauge panel.

I hooked 12 Volt Positive + directly to the left rear gauge terminal as seen from gauge face front.

Gauge case itself remained completely unconnected.

On the right hand gauge terminal I connected an EICO RTMA Resistance Substitution Box Model 1100
This lab resistance box took the place of the engine oil pressure sender rheostat variable resistor.
This allowed me to switch negative -ground resistance quickly just like the oil pressure sender does when screwed into the engine block oil gallery ground.

The other output side of this resistance test box was connected to 12 Volt Negative - power ground .

The oil pressure gauge was then connected as a simple DC Voltmeter as I described earler.

Here are my gauge readings & results.
Note: The old gauge's terminals were quite dirty & rusty.
I quickly cleaned them as best as possibe for this bench test.

Gauge & PSI Readings
15 ohms~~~Meter pegged over 80PSI
22 ohms~~~ 80 PSI
33 ohms~~~ 75 PSI
47 ohms~~~ 60 PSI
68 ohms~~~ 30 PSI
100 ohms~~~ 20 PSI
150 ohms~~~ 10 PSI
220 ohms~~~ 0 PSI

The gauge's needle moved very slowly during the switch from one resistor value to the next.
30 seconds between readings to get a stable reading.

This should give us all a good clue as to the original Teleflex sender's normal resistance operating range.

All readings were are not exactly precise~~~ but very close rounded up/down guesstimated readings!
{$pagetext}[/QUOTE]

Great bench test that will be a way to verify you temp, oil press, and fuel gauges to see if they operate.


What I am at a loss for here ~~SG~~ is if the gauge is a simple voltmeter??? why are there not any voltage readings here???

I see the terms resistance resistor ohm more than the terms volts voltage or a dc volt measurement???

the gauge reacts or measures to a changing amount of resistance, last time I read the basic princples of electricity resistance was all about ohm. sure sounds like what an ohm meter does doesn't ???????????

http://www.allaboutcircuits.com/vol_6/chpt_2/2.html

silverghost
11-23-2011, 01:27 PM
Matty, Jim & Guys~

I guess we could call it an Ohm meter , or a Volt meter ? ?
In reality it is doing both jobs.
It is measurig resistance (Ohms) from the sender , or voltage in the entire circuit.
A case could be argued for both names.
Let's call it an electric Oil Pressure gauge for argument's sake..

The key thing from my bench test is now we know the proper sender's operating range so a new sender can be found that works with this old 60s-70s Teleflex Oil Pressure gauge.

I also just tried putting my old gauge in the oven at 100* F for fifteen min.
This seemed to free-up the gummed-up & sluggish oil, or lube on the gauge needle's two movement bearings.
My gauge is now much more responsive.
Both Jim's & my old gauge have been sitting unused for decades now.
His is in fact virtually new.
I suspect the needle's old lube is gumming-up the needle & movement on both old gauges.

Perhapps this oil pressure gauge in the NOS panel is suffering from the very same gummed-up lube issue.
Heating-it up slightly might be worth a try.
As we know this gauge is contained is a semi-sealed can that is not really designed to open for future repairs.
Do not heat up ths gauge to too high a temp however.
100* F worked for me.

Matty, Jim & Guys~~~
Have a very Happy Thanksgiving Holiday !

Team Jefe
11-23-2011, 02:44 PM
This stuff is WAY boring....can't we just go take her out for a ride????:lookaroun:

JimG
11-23-2011, 02:58 PM
Gauge works fine. Sender is ok, too. Checked both this morning. I think I just have the wrong sender... I'll keep looking...

mattyboy
11-23-2011, 03:03 PM
that's half the battle Jim that's good the gauge works .

silverghost
11-23-2011, 03:16 PM
Jim~

It appears from my bench test that these old Teleflex Oil Pressure gauges need an electric sender with the value of~~~

Approx. 220 Ohms to 22 Ohms /80 PSI.

I would think a NAPA auto store should have such a genaric sender.

See if you can post the part number # here when you get the proper sender for the old Teleflex oil pressure gauge.

Good Luck; & let us know if you get the correct sender & how well it works..

JimG
11-23-2011, 06:50 PM
Thanks guys! Got the guages working, just bypassed the 6volt transformer and the gauges started working... calibrated against the Hd's and they are pretty close.

Now I need a fuel gauge to match...

Gary S
11-24-2011, 12:08 AM
http://www.ebay.com/itm/VINTAGE-TELEFLEX-FUEL-ROUND-GAUGE-w-BRACKET-P-N-35736-4-08-/200610101009?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item2eb54b3711

http://www.ebay.com/itm/TELEFLEX-357534-BOAT-FUEL-GAUGE-marine-gauges-/200679122177?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item2eb9686501

mattyboy
11-24-2011, 07:26 AM
Jim that is good news Gary has two leads for you those were the style gauges in my HM 67 16. I would also check out other boats they rigged like ski boats and others like Vance

mattyboy
11-26-2011, 07:19 AM
[ QUOTE=$originalposter]silverghost


Matty, Jim & Guys~

I guess we could call it an Ohm meter , or a Volt meter ? ?
In reality it is doing both jobs.
It is measurig resistance (Ohms) from the sender , or voltage in the entire circuit.
A case could be argued for both names.
Let's call it an electric Oil Pressure gauge for argument's sake..
{$pagetext}[/QUOTE]

for clarification


sg
there really is no guessing here the oil pressure gauge is not measurnig the voltage in the entire circuit it is measuring resistance in the circuit.

the gauges are simple meters( i'm not talking about the digital new merc stuff). each meter has it own job there are two basic types of meters used in your dash panel. they are meters that measure live energized circuits and meters that measure dead un-energized circuits depending on what they monitor dictates what type they are.

live meters are your voltmeter.amp meter,hour meters. these meters don't need and additional power source to perform their job. they get the power from the circuit they are measuring as they are part of the circuit.these meters only need two connections to work(not talking about the lamp function) a + and - or in the case of the amp meter an in and an out. these meters do not need a sender

dead meters are your oil pressure,fuel level and water temp . these meters need a power source to perform their job as the circuit they measure are un-energized. these meters have three connections + and - and a sender connection. These meters need a sender to work. they USE( not measure) a very small amount of voltage with very low current to measure a varying amount of resistance in the circuit provided by the sender . they are ohm meters and most ohm meters will be damaged if ANY VOLTAGE IS PRESENT IN THE CIRCUIT they are measuring. the voltage they use is so low that when shorted together it will not arch or spark. this works very well for your fuel system it is not a good idea to have voltage present that could short to a grounded metalic tank with gas in it or a grounded bad sender in a poly tank of gas, or having a sender go bad an sending voltage to your engine block.

a rose is a rose not a daisy

silverghost
11-26-2011, 10:41 AM
Matty~
The old Teleflex Oil Pressure meter in question here ONLY has TWO connections on it's back~~~NOT three.
The case itself is NOT part of the circuit.
The fact that it only has two connections is why I call it a Voltmeter.
If it indeed did have three connections then yes I would call it a true Ohm meter.
I guess I need to post some photos of this gauge in question if my slow web connection allows me to do so ?
These old 60s-70s vintage Teleflex units are a far simpler gauge than the much later units.

It's OK ~~~we both have differing opinions here.

mattyboy
11-26-2011, 01:03 PM
Matty~
The old Teleflex Oil Pressure meter in question here ONLY has TWO connections on it's back~~~NOT three.
The case itself is NOT part of the circuit.
The fact that it only has two connections is why I call it a Voltmeter.
If it indeed did have three connections then yes I would call it a true Ohm meter.
I guess I need to post some photos of this gauge in question if my slow web connection allows me to do so ?
These old 60s-70s vintage Teleflex units are a far simpler gauge than the much later units.

It's OK ~~~we both have differing opinions here.
Sg
You need to post a pic
What is the gauge made of and what are the connectors labeled?
How is the lamp connected

JimG
11-26-2011, 03:43 PM
Lamps are separate, mounted on either side of the panel. Two connections only.

mattyboy
11-26-2011, 04:21 PM
Lamps are separate, mounted on either side of the panel. Two connections only.
Jim
Are your gauges metal cased with metal brackets ?

mattyboy
11-26-2011, 04:29 PM
SG

Again you have me lost in your elaborate bench test you describe making 3 connections to the gauge but now it only has 2?

JimG
11-26-2011, 06:26 PM
All metal...

mattyboy
11-26-2011, 07:01 PM
yes Jim that makes sense the ground is made to the casing thru the bracket or thru the dash plate itself. on my stewart warners the bracket holding the gauge had a copper leaf that grounded the gauge's metal casing that ground was common to the gauge and the lamp power. the water temp gauge only had a 12 pos and a sender lug the ground was picked up thru the bracket and dash plate , the brackets actually had two sharp points that dug into the plate making it a ground passing ground from gauge to gauge. that was all fine and dandy till i put a plastic cased gauge in. i would bet a continuity tester would prove continuity between the gauge cases

silverghost
11-26-2011, 07:06 PM
Matty~

Re-read the bench test on post #24.
Only two single wire connections were made on the Teleflex gauge itself.
One was the Positive +12 Volt DC battery power wire.
The other gauge stud had a single wire going to my EICO resistor substitution box.
The other side of this lab test box went to the 12 Volt - negative battery ground.
This allowed me to put various resistor values in series with this simple circuit.

Basically a simple series circuit with the gauge & resistor lab substitution box in series to each side of the 12 volt DC test battery.

The resistor lab substitution box was then switched from one fixed resistor to the next higher, or lower, resistor value and so on to move this meter & check it's calibration & it's old sender's resistor value..


The gauge panel's lamps are fixed in a fiber insulation board material.
Each lamp has two wires.
There is no ground ` negative - connection anywhere on the gauge panel cluster; or to the metal gauge cans.
The gauge cans themselves are completely isolated from any positive 12 volt DC power ; or negative 12 Volt DC grounds.

Hope this test circuit description is clearer than mud ? ; )

Swing by the next time you are in my Philla area and you can do this bench test yourself.
I'll buy you a Pizza & some brews .

silverghost
11-26-2011, 07:25 PM
Matty~
There are NO negative - ground connections on this entire gauge panel, or the gauge can cases themselves ; and not on the brackets.

The panel & gauge cases complete with brckets are completely electrically isolated.

You have to remember that in their day
these gauges were often installed directly into wooden boat gauge panels and worked just fine without any ground negative - gauge case, or panel cluster , or mounting bracket connections.

Matty I know these gauges from working on these exact same gauges on mahogany wooden boat restorations.

M& E Marine Supply in Collingwood NJ used to sell these exact Teleflex gauges new until M&E went out of business just a few years ago.
They had tons of these old NOS Teleflex units in stock ; long after Teleflex stopped making them.

Trust me~~~
There IS NO gauge negative -ground connections anywhere on these gauges , or panels & the mounting brackets.

mattyboy
11-27-2011, 07:19 PM
Post pics please

mattyboy
11-28-2011, 06:15 AM
[ QUOTE=silverghost $originalposter]
Matty~
There are NO negative - ground connections on this entire gauge panel, or the gauge can cases themselves ; and not on the brackets.

The panel & gauge cases complete with brckets are completely electrically isolated.

You have to remember that in their day
these gauges were often installed directly into wooden boat gauge panels and worked just fine without any ground negative - gauge case, or panel cluster , or mounting bracket connections.

Matty I know these gauges from working on these exact same gauges on mahogany wooden boat restorations.

M& E Marine Supply in Collingwood NJ used to sell these exact Teleflex gauges new until M&E went out of business just a few years ago.
They had tons of these old NOS Teleflex units in stock ; long after Teleflex stopped making them.

Trust me~~~
There IS NO gauge negative -ground connections anywhere on these gauges , or panels & the mounting brackets.


Last edited by silverghost; 11-26-2011 at 07:29 PM.
{$pagetext}[/QUOTE]


sorry sg~ but you really lost me here there are no ground on the gauges at all?? are they electric gauges? or mechanical gauges? do they have a 12 volt connection? a sender connection?

mattyboy
11-28-2011, 09:23 AM
in an effort to try and document the different type of gauges and their connections

here is a pic of a 60's vintage teleflex fuel gauge you will notice the top of the gauge has the opening for the lamp . so with the lamp at 12 o clock there are three connections the 6 o clock connection is a ground. the 9 o clock connection is for the fuel sender and the 3 o clock connection is the 12 volts

these connections as i have said earlier are usually labeled (they can be lugs ,spade tip, or wire pig tails.)

s= sender
I = 12 volts from the ign switch
G= ground

the lamp on this gauge would look a pig tail and it would have a snap in collar that snaps into that opening. the lamp would only have one wire on it and go to the switch for the lights. the snap ring would connect to the ground of the case and complete the dc circuit when the switch is on( on this particular gauge you can see the ground tab for the lamp at 6 oclock posistion of the opening). I realize that Jim's plate uses common lamps that back light all the gauges thru a window or opening and that each of his gauges are not idividually lamped.

the ground lug at the 6 o clock would complete the circuit and energize the gauge when 12 volts is sent to the I lug when the key is turned to the on posistion. in the case of the fuel gauge it would imediately start reading resistance from the fuel sender if the tank is not empty. in the case of the oil press and water temp they bounce then zero out ( lowest reading) as a motor that is not running and cold will not have pressure or temp. SG if this ground is not present on your gauges please explain to me where the 12 volts you mentioned in your elaborate benchtest is flowing to???

hard to see but you notice that the bracket has bushings that isolate the two lugs. you see over the years the design changed not using the bracket lugs as the electrical connecting lugs. now today with wire colors in harness and the operating impedance of the senders being standard you find less difference in gauge connections.


again as i said earlier my older sw gauges did not have a ground lug on each gauge they picked up their ground thru the plate and bracket. I guess sw thought it made the installation a little neater with out a ground wire looping from gauge to gauge. So my sw only had two lugs for the sender and 12 volts but actually had a third connection of ground in the case.

mattyboy
11-28-2011, 09:43 AM
Jim G
you might be interested in where I got the pics from
http://www.ebay.com/itm/VINTAGE-TELEFLEX-FUEL-ROUND-GAUGE-w-BRACKET-P-N-35736-4-08-/200610101009?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item2eb54b3711

JimG
11-28-2011, 09:45 AM
Matty, mine looks nothing like that... It has no provision for a light, and has only two lugs. I'll try to take a picture...

mattyboy
11-28-2011, 10:07 AM
Jim
if it is an illuminated gauge it should have somekind of window or opening that the common light eminates thru to light up the gauge correct?.

the two lugs are for what connections? we are talking about the oil or water gauge right?

I know you have a plug for the harness where does the ground go on the dash side of the harness??

JimG
11-28-2011, 12:09 PM
The metal cases have windows for the light. Two connections, power and sender.

Matty, there is a good wiring diagram on post 4, second link, on this thread. Might clear it up 4 you...

mattyboy
11-28-2011, 12:38 PM
Jim,

that drawing is my point. I am pretty clear on this very simple dc circuit . in that drawing there is a ground shown on the volt regulator which goes to the lights and to the tach .

where does that ground on the volt reg terminate on the dash side. is there any continuity between that ground and the dash plate or the gauges ?

JimG
11-28-2011, 01:57 PM
Yes the entire panel is gounded to the white wire that is connected to the tach bracket. Continuity is present in all of the metal cases.

:banghead:

Now can someone help me find a fuel gauge to match? Without a light? Thanks!

penbroke
11-28-2011, 02:31 PM
The blue and white wires on the tach in the drawing I posted in the other thread are for the light (LP = lamp) in the tach. You can see in the drawing that the blue wire is hooked in parallel with the other lamps to the lamp switch. Other than a volt meter none of these passive gages need a ground to operate. It is only for the lights. The only reason the volt meter needs the ground is for a reference of zero volts.

Any kind of active gage either digital or analog would need a ground for both reference and as one side of the power supply.


Frank

mattyboy
11-28-2011, 02:54 PM
Yes the entire panel is gounded to the white wire that is connected to the tach bracket. Continuity is present in all of the metal cases.

:banghead:

Now can someone help me find a fuel gauge to match? Without a light? Thanks!

Thanks Jim I thought someone had re written the basic laws of dc electricity on me :)

Is the pic I posted the right gauge face? I will keep and eye out for you

mattyboy
11-28-2011, 03:08 PM
The blue and white wires on the tach in the drawing I posted in the other thread are for the light (LP = lamp) in the tach. You can see in the drawing that the blue wire is hooked in parallel with the other lamps to the lamp switch. Other than a volt meter none of these passive gages need a ground to operate. It is only for the lights. The only reason the volt meter needs the ground is for a reference of zero volts.

Any kind of active gage either digital or analog would need a ground for both reference and as one side of the power supply.


Frank

Not really sure I'm clear on your point about active and passive frank. Any gauge that needs a sender needs its own power source which would mean at 12 volt connection and a ground as well as a sender connection Jim's gauges have three basic connections a power a sender and a ground each of these connections are vital to its operation remove any one of them and the gauge will not work

penbroke
11-28-2011, 03:48 PM
The old un-powered gages we are talking about here are simple electro-magnets that rotate the needle against a spring. The amount of rotation is proportional to the current flowing through the coil of the electro-magnet. It is a simple series device much like a light bulb. The more power you shove through it the brighter it gets in the case of the bulb or the greater the rotation in the case of the meter.

Current flows from +12 VDC through the gage through the sending unit to ground. The sending unit is just a variable resistor that changes it's resistance in sync with the oil pressure of water temperature or whatever we are trying to measure.

These old tachs actually use the points as a sending unit and the ignition current to the points is supplied by the tach. That is why you see people here from time to time having trouble hooking up a newer tach in an old boat. Being part of the ignition circuit if tach failure would cause the engine to not run and the meeters themselves are rather delicate and easily damaged. Most of the newer tachs are "powered" and active electronics in them that count the pulses from the points and convert that information and feed it to the actual meter.


Frank

mattyboy
11-28-2011, 04:10 PM
The old un-powered gages we are talking about here are simple electro-magnets that rotate the needle against a spring. The amount of rotation is proportional to the current flowing through the coil of the electro-magnet. It is a simple series device much like a light bulb. The more power you shove through it the brighter it gets in the case of the bulb or the greater the rotation in the case of the meter.

Current flows from +12 VDC through the gage through the sending unit to ground. The sending unit is just a variable resistor that changes it's resistance in sync with the oil pressure of water temperature or whatever we are trying to measure.

These old tachs actually use the points as a sending unit and the ignition current to the points is supplied by the tach. That is why you see people here from time to time having trouble hooking up a newer tach in an old boat. Being part of the ignition circuit if tach failure would cause the engine to not run and the meeters themselves are rather delicate and easily damaged. Most of the newer tachs are "powered" and active electronics in them that count the pulses from the points and convert that information and feed it to the actual meter.


Frank
Frank by far the best explanation I have heard so far. If that is the case then a test of the sender wire off the sender with the key on and volt meter red to sender wire black to ground should show full battery voltage and current and the meter disconnected should show continuity across its two leads.



Frank with the ohm law of E= I X R voltage = current X resistance
in this old gauge setup what would be the constant in the circuit the voltage or the current cause we know the resistance is changing?

mattyboy
11-28-2011, 07:18 PM
Ok found the old two lug sw gauges did a quick benchtest they have 116 ohm internal movements. They send 12 volts to the sender lug from their ignition lug. So the movement is measuring a change in current in the circuit so these gauges are not ohm meters or voltmeters they are amp meters actually milli amp meters. So if the voltage is the constant and it should be in a system with a functioning alternator. Voltage stays the same and resistance increases current decreases conversely if voltage stays the same resistance decreases then current increases

Thanks frank it's crystal now

Gary S
11-28-2011, 08:04 PM
And here for reference is the back of a newer but still vintage teleflex
68931

penbroke
11-28-2011, 09:20 PM
"So the movement is measuring a change in current in the circuit so these gauges are not ohm meters or voltmeters they are amp meters actually milli amp meters. So if the voltage is the constant and it should be in a system with a functioning alternator. Voltage stays the same and resistance increases current decreases conversely if voltage stays the same resistance decreases then current increases"


That's exactly right.

When testing gages with a multimeter keep in ming that there may be a diode inside the gage to protect the meter movement from being hooked up backwards. If that was the case it would read the normal resistance (116 ohms in your example above) with the black and red leads one way and read open circuit(infinate resistance) with the black and red leads reversed.


Frank

mattyboy
11-29-2011, 07:29 AM
So are the new gauges any different? I was surprised to see the old sw fuel gauge works this way. The meters all have them same movement so they know how the needle will deflect to a given current. So all they need to do is mark the face with a name and a scale. What I have a problem with is that the gauge is sending 12 volts to the tank

I would think there is a better way

penbroke
11-29-2011, 08:45 AM
What's even more fun to think about is that the sender in the tank is a float on an arm (as I'm sure you know) that moves a wiper across an exposed winding of resistance wire. Like an old rheostat. Inside the tank...


Frank

mattyboy
11-29-2011, 08:55 AM
liking my old floor site gauge more and more........... a cork on a spindle with a needle on the top

sorta like the old compass you made in science class a cork with a needle on top ;)

Team Jefe
11-30-2011, 05:59 PM
Now I remember why I need to hire electricians........:confused:

mattyboy
12-01-2011, 08:55 AM
that's sound advice,more people are killed by improperly wired eggbeaters every year. it's number three behind people setting their house on fire with a turkey fryer , and having the TV fall into the tub while watching walker texas ranger.

Team Jefe
12-01-2011, 01:09 PM
be careful now....making fun of Chuck Norris could upset Chuck Norris and make Chuck Norris do VERY bad things to you:yes:68998 LMFAO!!!!:kingme:

JimG
12-20-2011, 10:24 AM
Still looking for that Teleflex fuel gauge... someone has just got to have one laying around from an old project?

mattyboy
12-22-2011, 06:32 AM
Still looking for that Teleflex fuel gauge... someone has just got to have one laying around from an old project?

Jim
Is the face correct on the teleflex gauge I posted? I need to know what to look for.

JimG
12-22-2011, 07:40 AM
Close, but no. I'm looking for the non-lighted version if possible. I know I won't find the exact one, (never seen another like the ones in my new-old panel) but would like to get close.

JimG
12-22-2011, 08:05 AM
See this thread for a closeup of the gauges...

http://www.donzi.net/forums/showthread.php?65494-New-(Old)-Bling-for-my-70-18-2-3&highlight=holman

mattyboy
12-22-2011, 11:17 AM
http://www.ebay.com/itm/TELEFLEX-357534-BOAT-FUEL-GAUGE-marine-gauges-/190616078781?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item2c619a89bd#ht_3171wt_1059


J (http://www.ebay.com/itm/TELEFLEX-357534-BOAT-FUEL-GAUGE-marine-gauges-/190616078781?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item2c619a89bd#ht_3171wt_1059)im this is the style gauge and has it own lamp . this is probably the closest you'll find they didn't make alot of fuel gauges most were sight gauges back then.

JimG
12-22-2011, 07:54 PM
Thanks Matty!

Someone has to have a vintage one laying around...