Rochester fuel sender removal

I have fuel tank senders with three wire connections labelled" pos,""neg", and "sender". The top of the senders are about 2.5 " in diameter
with two opposing flat slices. Unfortunately with the other fuel tank connections I am unable to get a good crescent wrench grip on the item to remove. My receiving gauges all read 1/4 empty
but I had some overflow at 30 gal upon filling. Rochester is of no help.The sender also reads "FULL EMPTY CGF24 12 volts Is there nny tool made for removing the senders" I would send pictures but I never could figure how to do that.

You can get a socket attachment, as I remember it is 2 3/8" from Napa or most auto supply stores, or use a large size basin wrench like this one from Amazon:
https://www.amazon.com/dp/B0009W77E6/ref=emc_b_5_t

Then I would suggest replacing the PITA cork floaters with a solid state device like the ones from WEMA:
http://www.wemausa.com/sensors/level...ater.shtml#S3U

They fit the Rochester threads exactly and WEMA will make whatever length you want. They are resistance powered, so you can use two of your existing wires and run to a new gauge (analog or digital), also available from WEMA.

thanks Mr Young: Ed at Samsmarine says my sender works with resistance to 30 ohms with 12 v fed into the 3 wire system
with 12 v across the neg and pos wire using a vacuum system instead of a float. I was able to get a
nut off the top of the tank which showed it filled to the top with diesel fuel. Tapping on the sender did not change the gauge
reading at 1/4 tank. I will try to run a few gal through the engine before once again tackling the sender removal job.