New Fuel Guage wiring

Just got a new fuel guage for my massey ferguson 135 and it doesn't look like the old one. Can anyone tell me how this thing wire up? My 135
has a one wire alternator replacing the old generator.

Haha! Confusing at first, isn't it? And the poor lableing on the back doesn't help any. I just went through this same thing. I actually had to disassemble my gauge to find out what was going on, but I'll save you the trouble.

Last part first... the stud between the ground symbol and the 12V lable is the ground. The "B" stands for battery (12V) and "T" stands for tank. I added a separate ground to a mounting bolt on my sending unit on the tank to make sure I was getting a good ground. And my fuel gauge works backwards. It's not ideal, but I'm smart enough to know I'm not gaining fuel as I mow.

Now, the reason why... the gauge is a "balance coil" type. This http://www.netlink.net/mp/volks/htm/fuel_ga.htm is a volkswagen site, but half way down the page is a good explanation of how a balance coil works.

Basically, you have a little magnet attached to the needle. You have two electro magnets that are almost balanced to cancel each other out and center the needle. In reality, the "empty" side is a little stronger and pulls the needle down. The sending unit is a variable resistor that parallels the "empty" side coil and "robs" some of its power. The resistance changes with the fuel level. As the fuel level rises, the resistance decreases, the "empty" coil gets weaker (more of its power is "stolen" by the sending unit), it gets overpowered by the "full" coil, and the needle swings toward full - and vice versa as the tank empties. So, there you go! Good luck.

Thanks for the explanation but, I can't see coasting through life with a backward fuel gauge. I put the old inoperative one back in and ran all new wiring to it
and low and behold, it is revived! I came off of the ignition side of the oil pressure switch for power but now the amp gauge reads high, not for sure why.