1949 Mercury 12v fuel sending unit

I believe the standard way of doing this is to use the stock gauge and sender with a voltage reducer before the gauge. Given the incompatibility of most senders and the poor quality of just about all of them, it should be a good reason to do it this way. It was good enough for Ford the first several years after they went to 12 volts.
 
tubman said:
I believe the standard way of doing this is to use the stock gauge and sender with a voltage reducer before the gauge. Given the incompatibility of most senders and the poor quality of just about all of them, it should be a good reason to do it this way. It was good enough for Ford the first several years after they went to 12 volts.
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I too have been given to understand that Ford vehicles, for several model years after changing-over to 12v systems, continued to use 6v gauges with a voltage reducer. DD
 
19Fordy said:
It looks good but, if it operates on the OHM's principle it will be a miracle if it provides accurate readings.

Go with the voltage reducer as suggested. Cheaper.
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I have to disagree with you about "looks good". First they say it fits '50-'55 Mercury. I believe that '49 and '50-'55 Mercury's used King-Seely gauges and should be the same. Also, to me, it looks cheap. I addition, I believe that anyone selling these should know enough to say what system (resistance or King-Seely) their product operates on. This ad doesn't specify which it is, but really should as it is an important factor.
 
You can purchase the original style Ford volt drop cheaper than the new sending unit. Check e-Bay for" instrument cluster voltage regulator". The average price is about $25
 
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Folks have been selling Ohms type senders for years claiming that they will work so this is nothing new. If a person wants to use an Ohms type sender then they should be prepared to replace the fuel quantity indicator with an Ohms type indicator that works with the same Ohms range as the sender. There are quite a few different Ohm ranges currently available depending on what automobile make the system is for. This link shows a lot of the different Ohms values.
https://www.tanksinc.com/index.cfm/page/ptype=results/category_id=159/mode=cat/cat159.htm

As was mentioned, the original King Seeley units don't work with Ohms principle. They are a current based system that uses a heating coil on a bi-metallic strip with a very small set of points that open and close rapidly like a voltage regulator to send a current value signal to an indicator that is calibrated to work with that function of current transfer between the two components..
 
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1949mercury said:
Anyone find a good 12v fuel sending unit they like. Not the crappy plastic one that holds the sending arm ?
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You have not said why you are looking for a 12 volt sending unit.
As stated a couple of times in this thread, if your original sender is good all you need is a late 60's Ford Mustang instrument panel voltage regulator, available from NAPA or other vendors.
That is what I am using.
459046
 

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Here's what the 49-51 Merc gas tank sending unit looks like and how it operates as shown in the 49-51 Mercury Manual. Have to admit that the aftermarket unit shown above doesn't "look" as good. More importantly, it won't read accurately through it's range of motion if used with KS gauges.
 

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I’m asking because when I put the car together and switched to 12v I figured I would get a new 12v sending unit. I got a 6v-12v 10-73 ohms sending unit from Dennis Carpenter & when I was making the lever the correct size I broke the plastic piece it goes in. They replaced the sending unit even though it was my fault. I do have the reducers on my stock gauges and the gauge reads full when filled but it goes really fast to empty. I fill it up & only 8 gallons so half full. I had a shop look at it and they added a Meter Match. It sets the ohms for any sender once it’s set to full & empty. They said it was fixed. Gauge said full but after 5 minutes of driving it went to 1/4 tank. The shop looked at it again said it was fixed but did same thing. I pulled the sender from the tank and the float was sitting at the bottom of the tank broken in the same spot on the plastic piece. So I’m looking for a good one.
 
1949mercury said:
I do have the reducers on my stock gauges and the gauge reads full when filled but it goes really fast to empty.
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If you in fact have a reducer on the gas gauge, this may be the source of the problem.
Perhaps a call to Carpenter to check with them.
 
The tank unit is a ground for the gauge, the power comes from the gauge through the sending unit to ground. The sending unit controls the current follow to ground. The voltage drop goes on the inlet side of the gauge.
 
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