Mayfair Float Switch and Bilge question

chris16371

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So I'm trying to figure out the wiring for the bilge pumps and the Mayfair float switch on my boat. I found 2 good wiring diagrams on here so once I figure out which wire is which I'll be good to go. I'm assuming the black wire on the bilge pumps is the negative? Then for the float switch I have 2 brown wires, one is solid brown and the other brown with silver writing on it and I'm wondering which one goes to the pump and then to the dash switch. When looking at the float switch with the wires closest to you does the left or right wire go to the pump and then to dash switch?
 

Scott Danforth

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with the switch, it doesnt matter. one wire goes to power, the other to the pump
 

Bondo

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Ayuh,.... The float switch is make or break, direction don't matter,....

You should wire from full time power, through the float switch, to the pump,...
The switch on the dash should go directly to the pump,...
The dash switch is to over-ride the float switch,...
 

chris16371

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So one straight to positive on battery and the other joins the pump then those go to the dash switch then to battery positive? Doesn't matter which wire I use as long as 1 goes straight to battery and the other to switch and pump? Of course there will be fuses installed also.

The diagram I looked at showed a brown wire with red stripe straight to power and the other solid brown to pump, switch, then battery. There was no mention of either wire could be used either way so I wasn't sure.
 

chris16371

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Also for the live well pump I will just wire to battery and dash switch correct?
 

alldodge

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Bilge pumps require only 2 wires, since yours has 3 wires it sounds like you have a bilge pump and float switch combination. If this is the case then the brown is connected to 12V power, and the Brown/White is connected to a helm switch for manual operation.

If your pump does also contain a float switch then you don't need to use an additional float switch.

Also for the live well pump I will just wire to battery and dash switch correct?

Yes, but also make sure its fused
 

chris16371

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Bilge pumps require only 2 wires, since yours has 3 wires it sounds like you have a bilge pump and float switch combination. If this is the case then the brown is connected to 12V power, and the Brown/White is connected to a helm switch for manual operation.

If your pump does also contain a float switch then you don't need to use an additional float switch.



Yes, but also make sure its fused

Sorry if my wording was of confusion but each bilge (one is for live well) has only 2 wires, one black and one brown. Then I have the Mayfair float switch which has 2 wires also, one solid brown and one brown with silver lettering. My understanding of the diagram for float switch and bilge pump is brown on bilge to one of brown on float switch then those go to dash switch and from dash switch to positive on battery, then the other brown on float switch goes straight to battery positive, black on bilge straight to negative. Then for the live well bilge pump it goes black straight to negative and then brown to dash switch to positive on battery. Then of course I will have it fused, the fuse should go between the dash switch and battery on each correct, not before the dash switch? I attached the pic of the diagram I found on here, I'm going to wire exactly like shown unless anyone see's an issue with the diagram. My main question was in the diagram it shows brown with red stripe goes straight to battery but I don't have a brown with red but from the replies it seems it doesn't matter what brown wire goes straight to battery and which one joins the brown bilge pump wire.

 

chris16371

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Thanks to everyone who helped make this clear to me, even though my wording may have became confusing.

Another question I have is will there be a draw on my battery even with the dash switch being off? I always connect my battery maintainer when not in use but I'm just wondering for when I'm out on the water and the motor is not running. I don't think my motor has a pull start on it so making sure my battery doesn't drain is important. It's a 1973 Mercury 500 50hp, I haven't looked in depth at the motor but there's no visible pull start on the outside of the motor. I also believe the motor charges the battery while in use but I may be wrong on that, will have to check the manual. I do carry a small jump box so I'll be able to jump it if I have to but knowing if there's a draw on my battery is still something I should know.

I have 5 different dash switches already on the boat, should I wire my fish finder into a dash switch as well and should it be fused also? Idk if the fish finder will have a draw on the battery if it's ran straight to the battery without a dash switch.

Appreciate the help everyone!
 

alldodge

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If things are OFF there should be no draw from anything, including the bilge pump. Draw only occurs when the pump is turned ON by the float switch. The motor would not draw anything unless there is a problem with the motor, and it does charge the battery when running. The fish finder switch is good to turn it OFF.

If you had a battery switch or main power switch at the helm they could be used to turn everything OFF
 

chris16371

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I'm back with another question. Can I wire 2 wires to one fuse, such as the live well and bilge or float switch that goes straight to battery and the one that joins the switch? If so would I just use a higher amp fuse, would a 10amp be enough but not to much? I forgot about the stern lights, I'm assuming I should fuse those as well so I would need to join those to one fuse as well, I'm not sure what amp I would need for 2 stern lights on one fuse. I would of bought more but unfortunately they only had 4 waterproof fuse holders left. Also for the stern lightsl socket there's only one wire that runs to the positive correct? No ground wire? I believe it grounds to the socket but I'm wanting to make sure. Thanks
 

alldodge

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Yes, but you should not do it. If you have 5 items which need a 3 amp fuse, then if a 15 amp fuse could protect the wire feeding all circuits. The 15 would protect the circuit but it could cause the burning up of everything on the circuit before the fuse blew
 

chris16371

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Yes, but you should not do it. If you have 5 items which need a 3 amp fuse, then if a 15 amp fuse could protect the wire feeding all circuits. The 15 would protect the circuit but it could cause the burning up of everything on the circuit before the fuse blew

I might just hold off on wiring the stern lights then so I can get 2 more, one for each light. I believe I have enough for everything else. 2 for bilge/float switch, 1 for live well pump, and 1 for fish finder. I think the stern lights are the last I need, for now anyways.
 

chris16371

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Well I have bad news, both pumps must be bad. I spent all afternoon running and connecting wire and making sure I did a job, at least all my wire is in place for when I put in new pumps. After I had everything hooked up I flipped the dash switch and nothing, same with live well pump. I thought maybe the switches were bad since they looked old, I had a couple of toggle switches on hand so I hook them up and nothing again. I ended up cutting the pump wires and placing them directly on battery and just had spark for both but they wouldn't run.

Tomorrow I'm going to but 2 new pumps. I'm going to get either a 1100gph or 800gph for the bilge, whatever the biggest field and stream has. For the live well what would be a good size? I think they have them as low as 500gph.

Is there a way for me to test the float switch to see if it's good? Being that both pumps are bad I'm not very confident.

Last question's (for now): Do I need a 3 way switch (auto, off, on)? If so how should I wire it?

Thanks!
 

alldodge

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With how your wiring in post 7 all you need a SPST toggle switch for each pump

To test the float switch use an ohm meter

The size of the live well pump depends on how big your well is and how much water you want to move.
 

chris16371

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With how your wiring in post 7 all you need a SPST toggle switch for each pump

To test the float switch use an ohm meter

The size of the live well pump depends on how big your well is and how much water you want to move.

Thank you, I'll continue to use the switches I have then. My live well is about 24"Lx18"Wx18"H, I wouldn't think I would need anything more than a 500gph but this is my first live we'll so I'm not exactly sure.
 

Glaspar_Fan

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To your question about a 3 position switch, there are two methods for wiring a bilge pump. You are using the favored method which assures the pump will always go on when the water level rises in the bilge. To be clear, that is the method I use when installing a new pump. The second method, which is common OEM wiring on the old boats I have experience with, uses a 3 position switch. The circuit allows the pump to be off, automatic (float) or on. In the off position the pump will not run even if the boat is sinking. So why would you want that? To keep from pumping oil or gas into the lake/ocean when you have a leak. Maybe the old float switches would float in anything, but newer float and electronic switches will only float/switch in water, not gas or oil.

Last year I had first hand experience with this. Hauling the boat up to Long Beach to launch shook the old tank enough to rupture a heavily corroded spot. When we got to the ramp I could smell gas as soon as I walked back to the boat. The bilge was slowly filling with gas from the leaky tank. So disappointed, I wasn't thinking straight and just headed for home. About half way home I remembered the hardwired bilge pump and about freaked out. Can you imagine pumping the bilge gas onto the freeway at speed? Other drivers might have objected. That was also when I realized the switches were not activating in the gas. Reading about the switches later it actually says they will not switch in oil or gas. If it ever happens again though, I'm pulling the fuses before getting on the road.
 

sam am I

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Glaspar_Fan

I have the same thoughts as to a 3-way switch with an "off" position as this would be my worst nightmare (mooring night sweats for sure in my case), as such, I use the hard-wire to a float with second path to a helm mounted SPST as a manually override in what you state as "the favored method".

As far as if the float floats in oil or gas and energizes the pump, mine might, might not BUT, if it does ever and it starts to pump gas/oil out into the lake or road, I'd (couldn't you?) just pull the fuse in the hard-wired feed that goes to the float and shut that feed off. If not, that hard-wire feed path really should be fused close to the battery.....Just say'n
 
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chris16371

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Appreciate the replies everyone, lots of good info to absorb! I ended up with a 500gph aerator pump and 800gph for the bilge pump, I didn't think I needed the 800gph for the live well.

What ohm should the float switch read? I didn't have time to test it before I left, I didn't buy another either so hope it's ok or I'll be making another trip.
 

alldodge

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What ohm should the float switch read? I didn't have time to test it before I left, I didn't buy another either so hope it's ok or I'll be making another trip.

Infinity when down or OFF, an zero ohms when up of ON, just like a toggle switch
 
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