View Full Version : Bilge float switch stuck

07-07-2005, 09:48 PM
Right out of storage this spring the bilge pump on my 99 Mobius quit working. With some help from Brian R. and my local maint. guy I got it running by simply removing the cartridge and spinning the vane manually (it gave a 'click' and then started spinning freely again)

Now the other shoe - the float switch appears to be stuck. The bilge is running all the time even when no water is there to pump. I tried rapping on it with a wrench but no luck. Right now I am stuck with disconnecting the battery when I am not using it.

I have recently started manually draining from the drain plug to get more water out. Could this have left the switch dry? and caused it to hang up?

Any ideas - or just replace the whole assembly. What about flooding the switch with the power off to encourage the switch to free up?

All ideas welcome.
I know a bilge/float assembly is not that expensive, but it does not look like it is that easy to get out because there is a bulkhead very close to it.


07-07-2005, 10:22 PM
Run a hose to it and wash it out.

Typically they twist and come off the floor, base plate stays attached to boat. I do not know if this works with SC but it does with my duck boat so I can clean the gunk out.

Worth a shot.


07-08-2005, 12:54 AM
I can get the pump cartridge out, but the float switch is a separate assembly. It seems to be pretty secure to the floor. The pump is working fine now, but the float switch is always on.


07-08-2005, 08:21 AM
My bilge did the same thing. Then I had to just turn it on by the switch on the dash, which wasn't too bad as long as I was there to do it. I replaced the whole thing, pump and float switch, for about 30.00. Walmart carries the Attwood line. Snipped a couple of wires, covered those with liquid electricians tape and screwed it back to the floor. Hardest thing about it was getting to it and the limited room you have to work with.


07-08-2005, 09:46 AM
Try using compressed air and see if you can dislodge anything that may be stuck in it. If the float is sticking on its own try spraying some WD40 into the housing to free it up.

07-08-2005, 09:49 AM
Try using comressed air to try to dislodge anything that may be stuck in it. If the float is stuck on its own, try spraying WD40 into the housing to try and free it up.

07-18-2005, 03:37 PM
Adding to the confusion.

I got the access plate off so I now have easy access to the bilge and switch. I tried cleaning the float switch, but it appeared that the float was not stuck. So I assumed it was in the electronics of the float. So I cut the wires from the float switch to "wherever it goes'. The bilge continues to run with the dashboard switch turned off.

So it would seem that either:
1. The dashbaord switch has some wierd short in it.
2. The circuit board behind the dash has a short
3. An open in the float switch tells the bilge to run?

In the mean time I have pulled the connector off the circuit board so the bilge will not run at all. At least this way I do not need to always be disconnecting the battery to stop the pump from draining the batt.

Anyone have any ideas I would appreciate it.


07-18-2005, 07:22 PM
Yes, Dave, I'll bet I might be able to help.

Remember, I have the 99 outback, which is the stripped-down mobius that year.

10 days ago we had problems and replaced the original bilge pump with a Rule #750.

The original wasn't working on auto. Just on manual. Actually, had the reverse occured, it would have been by chance, based on the wiring mess I encounterd.

The original set-up ( I'll bet yours is the same ) is pretty cobbled-up.

Three wires from the dash, converted under the floor near the pump to a four-wire set-up. Plus, extension wires were grafted-in. For us, the crimp-on connectors corroded. One had fallen-off. The others pulled-free when tugged. The whole mess was wrapped with electrical tape from the factory. Based on what I saw, the wiring could possible fail and cause it so stay on all the time. Hard to explain, but check yours and see if I'm right. The other idea, smokedog, of flushing is legitimate, also.

Solution for us: Find the basic three-wire set-up, under the floor near the pump, before all the grafting crap. Cut there, and either install a new three-wire pump with built-in float, else, figure out the wiring ( its easy ) and reattach the old unit. Re-do the connections with new crimps. It'll last another few years!

The Rule 750 was about $45.00 at boaters world. Probably 0 markup or more. It pumps more volume than the original.

I struggled with this for 2 seasons before I got serious and fixed it.

To test the original float and pump, remove both and test on the bench with a meter, else, against a battery directly. Easy to remove and re-attach if need be.

Hope some of this helps.

07-18-2005, 11:39 PM
Thx Catdog. This pretty much agrees with what I am seeing. I did not unwind the electrical tape at the junction of the 4 wires. I was thinking that they might be using a special anticorosion sealant that I would not be able to replicate. If it is just electrical tape I think I can manage the works myself.

Hopefully this means I do not have to worry about the switch or the circuit board. I will give it a try this weekend.


07-25-2005, 10:38 PM
So I have now replaced the Mayfair 500 gph pump and automatic float switch with a new 750 gph Mayfair with new automatice switch. The new switch came with three wires, a black, a brown and a a brow with stripe. The old switch only had two wires (no black).

You guessed it - bilge still runs full time. I am not certain I have the wiring right. I connected black to balck, brown to brown, and stripe to stripe . I also reused the existing wiring and connections since they appeared secur and I thoought I could still cuthe them out if needed.

I am starting to think that it may be the dash switch. When I turn the bilge on from the dash the pumps seems to spin up faster.

I took a look behind the dash and was able to find the wire to pull so at least I am not disconnecting the battery all the time.

But I can not for the life of me figure out how to get that swtch out of the dash. Do I need to take the whole control pannel off? If so does it just pull off the swtiches. It looks like all the spade fitting on the switches is all that is holding the board to the dash.


07-26-2005, 11:09 PM
Try switching the two hot leads.

The striped wire on the Rule 750 did not match-up to the striped wire coming from the dash. It caused the pump to run all the time.


Striped to brown pump.

Brown to striped pump.

For ours, that worked perfectly!

07-26-2005, 11:44 PM
SO I guess trial and error will have to prevail.

It would be nice to know where to put a meter on the circuit board so I can rule out the dash switch.

Did the Rule 750 have three wires on the float switch? The Mayfair 750 has black, brown, and striped, whereas the mayfair 500 (stock) only had brown and striped.

Thanks for ideas.


07-27-2005, 05:07 AM
For the switch on the dash, all you need is to check is for continuity...put the probes from the meter on each side of the poles on the switch......with the switch off, the circuit should be broken..........on, and the lil electrons should boogey down the pipe.
Hope this helps

07-27-2005, 10:08 PM
Right. Just needs a simple radioshack meter for that.

Yes, the Rule and Mayfair sound the same.

Coming from dash, one wire will be the ground. Should be black. It goes to the motor.

Another will be hot all the time, regardless of switch position. It goes to the float switch.

The third will be hot only when the switch is in the on position. It goes to the motor.

07-28-2005, 12:57 AM
Thanks for sticking with me on this.
Getting to the switch poles may not be that easy. The board is pretty crowded back there and the work space uncomfortable to say the least. That was why I was hoping it would be easy to get the switch out so I could check it out of the dash.

Catdog - The wiring scheme you propose makes sense, but there are three wires coming from the Mayfair switch.
So I see Brown from switch to brown in harness.
Black - don't use from switch, just connect motor black to harness black. (right now I have the black from the switch and the black from the pump connected to the black in the harness.)
Brown with stripe from switch connected to brown with stripe for pump and harness??

The instructions that came with the new pump/switch were very confusing so I bailed on them.

I will try this weekend.


07-28-2005, 07:47 PM

I'd leave the switch alone for now. Don't worry about it or the circuit board. Unless I missed something, you will be ok.

I'd cut the wiring harness back to the 3 wires ( you may have already done this, down under the floor panel, right?)

I'd connect the brown striped wire from the harness to the brown plain wire from the pump.

Then, the brown plain wire from the harness to the brown striped wire from the pump.

( This is what I had to do. Moomba wired the thing backwards, essentially, from the convention used by the pump manufacturers. At least on mine. )

And the black to the black.

Give me an email address and I'll send you my phone # if you want.

07-28-2005, 07:49 PM

If the Mayfair has a built-in float switch, you know that you discard the moomba float switch along with the old pump, right?