Bilge pump / switch issue

[Carl]

I'm having a problem with my bilge pump and wondering what others think of the problem and my approach to fixing it.

Late last year at the end of the season I noticed that the pump was running with the three way switch in Auto without the float being raised. It was not running full speed, but more like slow humming. I finished the season and promised to fix it this spring. The pump was 3 years old, the float switch, the three way switch and all wiring in between was replaced last spring. (all products are Rule) I bought a new pump (1100 gph) and installed it, filled the bilge and it pump like a champ with the switch in Auto. A while later, I hear the pump running again (bilge is empty) and I notice the pump is running - but not full speed - just a low hum again. I play with the float switch and stops, but then starts again. With the switch up it runs like it should. I checked all the wiring connections including at the 3-way switch. All seem good.

My first thought is to replace the float switch for two reasons - 1. because I think that is the problem and 2. because it is still under warranty (and I have the receipt ).

What do you all think.

I'm going to keep the old pump (800 gph) anyway because now I think it might still be good and wire it up with alligator clips and 10' of hose like someone had suggested on another post a while back as a back up.

Carl