Selecting the right gauge senders - American vs. European
What is the difference between European and American Resistance Senders?
The resistance is how the gauge and sender talk to each other. The sender supplies the gauge with a resistance which the gauge then displays on the dial.
European and American resistances are different from one another.
A European resistance fuel sender will have an output of around 10 Ohms on empty and as the fuel level increases so will the Ohms, while an American resistance fuel sender will have an output of around 240 Ohms and the resistance will decrease as the fuel level increases.
This is why you must match the resistance of the gauge and sender, as the most common problem we hear is when this has not been done correctly, so the gauge will be reading the opposite to what it should read.
What type of senders do I need, standard or insulated earthed?
First of all, let’s explain what standard and insulated mean.
Standard earthed senders tend to have one terminal which you connect to the signal wire from the gauge, and the sender earths itself through the engine.
Insulated senders tend to have two terminals, one terminal is for the signal wire from the gauge and the other is to run to an earth/negative terminal on the battery.
So, the first thing to check is if your engine is standard earth or insulated earth. A good way to do this is to see if the negative terminal of your starter motor is connected to the engine. If it is, then it is more than likely that your engine is standard earthed and you can use standard earthed senders. If you find it is connected to the negative of the battery then you are best to use insulated earthed senders.
If in doubt we recommend consulting a qualified and competent Marine Electrician.
Do I need dual or single station senders?
This depends on how many instrument positions you have.
If you have two positions and you would like both positions to display the engine information, you will require dual station senders as each sender can supply two gauges.
If you only have one steering position then you will require single station senders as the sender will only be supplying one gauge.
