may help...
I am new here, but I just had my sending unit out this Saturday. The old 95' I bought had been sitting up for about 4 years and one of the problems it had (because it had 1/2 tank of gas in it these 4 years) was the floats were all seized up. I haven't got mine running yet, so I don't know if I fixed it, but I did get them un-seized. But I only wrote to tell you that it only looks complex, mine had four floats on it that each had a range, each range was blocked off from the next with snap rings. From what I found, I think depending on where each float is on the rod, there is a different resistance between the 2 wires coming off of it. So I don't know how much you messed with it, but possibly some of your floats are seized as well? If so, just work them back and forth a bit. Just thought I would share what I have learned in my very short experience with the 'underhood' of a jet-ski. Hope this helps!