WEMA
You should contact WEMA directly. Look at the top of your WEMA water gauge and record the model or part number then talk to the tech people on the WEMA site. It seems there are different models with different internal resistant characteristics, some that will only work with some gauges.
I had an original and defective WEMA water tank sensor on my 2000 H340. I could not find a suitable replacement match on the WEMA web site so I contacted them at
info@wemausa.com. It turns out that the Hunter factory installed water tank sensor on my boat (marked 01-00, W2-17-H336) is a now discontinued model and has been replaced with the WEMA S3 series. This is a 0 to 180 ohms sensor and is 17 inches long. Curiously, the unit on my boat is a European, screw-in sensor which is mounted in a standard five-hole American style adapter ring. The gauge-compatible replacement for my boat is the European sensor # S3-432.
I had to deal directly with customer service at WEMA via email and phone and they were very helpful. As it turns out, you cannot purchase the new S3 sensors from the web site. The online sensors look the same but the ohms are different. The ones on the website are 240 ohms at empty and 33 at full. The replacement sender I needed is 0 at empty and 180 at full. If you order online, you will need the entire system (gauge + sender) to make sure the units are compatible. I had to order my new sensor by phone directly from WEMA. Their contact number is on their web site.
I ordered a new sensor and was able to unscrew the old one from the mounting ring. It seems that Hunter sealed the threads with some unknown caulking. I was able to break it loose with heat from a hair dryer
