Fuel sending unit

The only info I have is for a 2006 284. 85 Ohms full (up) and 10 ohms empty (down). If you have the same instrument in the dash it is likely these values will be the same for the 354.

An open circuit between the instrument and ground (through the sender) will cause the gauge to show full. A short circuit will show empty.

With the hot wire removed from the sender you should see about 5 volts and a full reading on the gauge. Ground that wire and it should go to empty.

Hopefully someone else will have exact numbers for your tractor, but at least this might be a starting point.

good info.

Roger wrote:

Thanks for the info. I should also have asked if anyone knows of a particular brand of after market fuel gauges that would work with the oem sending unit? Thank you in advance for any info.

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You will first need to determine what type of sending unit you have, a magnetic type or a thermostatic type. Then you will have to match the ohms resistance to the gauge scale. You will need data sheets for this.

So if you want to take the time and trouble, and maybe someone already has, the answer is yes. Otherwise just buy a new Chinese gauge or sending unit, or buy a complete aftermarket set which in all likelihood is made in China anyway.

I took mine apart after replacing it just to see what was wrong. It is a simple wire wound resistor with contacts on either side. The contacts were worn to the point they were intermittent at best and completely open most of the time. This gave me a false reading of full.

Yes, you can test the sender by putting an ohm meter (DMM or Digital Mulit-meter set to read ohms) across the terminals of the sender and moving the float arm up and down. You should see a higher value with the arm up and a steady reduction in the reading as you slowly move the float to the down position.

For basic troubleshooting the actual numbers are not as important as seeing the value change as you move the float from top to bottom.

What symptoms were you seeing that lead you to ask about the Ohms values in the first place?

Hmm. I would have to see specs and instructions to give sound electronics advice.

If your new gauge requires more resistance than provided by the factory sending unit, it should be a simple task to add the appropriate sized resistor in the line from the gauge to the sender.

Can you provide a schematic or instructions for the new gauge?

My 20 hp tractor had no fuel gauge but had the access hole for one, I bought a universal marine fuel tank gauge  kit so it came with 2 inch gauge and sending unit. works great just trim float stem to what instructions say to cut to that type and shape tank.

DavidPrivett wrote:

My 20 hp tractor had no fuel gauge but had the access hole for one, I bought a universal marine fuel tank gauge kit so it came with 2 inch gauge and sending unit. works great just trim float stem to what instructions say to cut to that type and shape tank.

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That’s my recommendation too. Would save a lot of time and anxiety.