Tip for Bilge Pump Float Switch Mod

[Finest Kind]

Ever happen to you?
The in line fuse for the stern bilge pump was blown and I noticed a bit of water was still left in the bilge...
When I replaced the fuse, the pump came right back on and pumped out MOST of the water sitting there, then as the water level dropped the float switch shut off the pump (as it should)..BUT some of the water remaining in the length of hose running from the pump to the discharge flowed back into the bilge and kicked the pump back on again...and the water was pumped out, the motor stopped, the water sloshed back through the hose, the pump came on, then the pump went off...and it repeated again and again...

So my fix was to zip tie a small fishing weight onto the float switch lever close to the hinge end.
The added weight was enough to stop the float switch from coming on when that back flow surge came through the hose, but still allows the float switch to do it's job and turn on the pump when there is enough water in the bilge to fully float the switch.

 

[jbrinch88]

Good idea, as long as it works. I usually mount the float switch a 1/4" higher or so with a piece of starboard or whatever.

 

[Finest Kind]

Good idea, as long as it works. I usually mount the float switch a 1/4" higher or so with a piece of starboard or whatever.

The float switch is already higher than the pump intake by about an inch. The problem was the "surge" of water coming back through the hose as soon as the pump stopped. This surge was enough to activate the float switch again. This issue would happen whether the switch was mounted 1 inch, or 1 foot above the pump intake, due to the design of the switch. It is a cheap Chinese knock off of the Rule 25 and floats a bit too much. The added weight now allows it to come on when there is enough water to submerge the float arm, instead of when the water just touches the float arm.

I wish Rule still made the original Rule 25 Mercury switches, they lasted a LONG time. The new mercury-free Rule 25A switches are CRAP and also made in China now, (look up the reviews on Amazon), so I bought the equally crappy knock offs for $10 bucks a piece. I changed one in Nov this year, and just had to change it again last week before doing the Mod to it.
I have to always keep a spare in the dock box now...