# Bilge pump float switches



## Brian121804 (Apr 2, 2019)

Are they all just crap?

Finishing up rewiring my little 14 foot Mirrocraft.
I bought all high end components and installed 
it the right way, have a stupid amount of $ into 
this already. 

I'd like to add a float switch for my bilge pump,
as I have a few longer trips planned, & the boat 
will be docked for a week or so at a time. 

A little research shows mostly bad reviews (which 
I always take with a grain of salt) for all of them. 
The Rule 35 ($30) seems to be the most popular,
then there are any number of others at $15 or less. 

Not a huge amount, but if they're all about the 
same quality I'll go cheap, seems silly to spend
$30 or more for a switch for my $10 pump.

Anyone have any personal experience to offer?


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## DaleH (Apr 3, 2019)

I stopped using Rule pumps many years ago and never looked back. Have installed a couple dozen to maybe 3 dozen Johnson (or Marpac brand as they are Johnson pumps) pumps, field effect (no moving float) switches and high water alarms ... and have yet to have one fail. 

Only failure I have personally seen on a Johnson item was the pressure switch on a 14-year old combo livewell/washdown pump in my brother’s Grady White used in saltwater. Replaced the switch assembly and that pump is still working!

Buy online from your favorite Seller. The Johnson ‘electronic’ (field effect, no moving parts) bilge pumps switches are bullet proof ... just keep them clean.

Oh, for connections in the bilge, like any butt connection, use a long piece of adhesive-lined heatshrink at least 3-4 times longer than the connection and I seal the ends of the connector w/ some goop like BoatLife Life Caulk or 3M 5200 before putting the HS over it. Have never had a failure of any wiring run I’ve done myself either ...


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## Brian121804 (Apr 3, 2019)

Thanks Dale.

I see a couple different Johnson switches. 
I'm pretty sure you're recommending the 36303 Ultima? (2nd link)...

https://www.amazon.com/Johnson-Pump-36152-Switch-Elec-Mag/dp/B000KOKJTS

https://www.amazon.com/Johnson-Pump-America-Marine-Control/dp/B000N9RF1K


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## DaleH (Apr 3, 2019)

Yes, $46 for a e-switch only? OUCH, as online from a discount boat parts seller you used to be able to buy the bilge pump w/ electric switch built-in as one unit for about $65.

Here’ an auto 800gph one, pump & field-effect switch, $69. See: https://www.ebay.com/itm/Marpac-800-GPH-Automatic-Bilge-Pump/254172278414?epid=1622306613&hash=item3b2dd92e8e:g:fdoAAOSwirZTxYiw:sc:USPSPriority!02180!US!-1

I believe they also make them in a smaller 500 GPH rating.


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## Brian121804 (Apr 4, 2019)

Thanks again for your insight.

Yeah, I see the 500 GPH for ~$50, I'll eventually install that.
No immediate need, so for now I'll just carry on with my manual toggle switch.
I already have the SPDT switch & additional wire in place, so it'll be a simple install.

I shoulda known I wasn't gonna get off cheap.


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## JL8Jeff (Apr 4, 2019)

Some of the float switches have a metal ball inside that rolls down when it floats up to make contact to run the pump. I've had that style give me problems when the metal ball gets stuck inside and doesn't roll down. There are mercury switches which seem to be much more reliable, I've never had a problem with that style.

One thing to check with your bilge pump is to test it in the driveway running a hose in the boat to watch it pump the water properly. I had one pump that would get an air pocket in the outlet line and it would run and not move any water. I got lucky and saw it happen when the boat was on the side of the house and we had a quick little downpour. I had to keep reconfiguring the outlet hose until I was sure the air pocket issue was resolved. When you do put in a float switch, test out everything in the driveway first.


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## Brian121804 (Apr 4, 2019)

As far as I can tell mercury switches are no longer available.
All of the mechanical switches seem to be problematic.
Electronic switching looks to much more better, albeit somewhat more expensive.

Glad to hear you didn't sink in the driveway. :wink:


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## JL8Jeff (Apr 4, 2019)

Actually, it looks like the current float switch in my boat might be the Rule 35A which is mercury free. I thought it was a mercury switch but it appears it isn't.


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## Brian121804 (Jul 20, 2019)

Well, I bought & just returned an Ultima 600 to Amazon:
https://www.amazon.com/gp/product/B000R4PFUO/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

The field effect switch seemed to work well, however the pump cavitated about halfway between the high
and low limits. It would stop pumping water and never shut off. Move the discharge hose over to the $10 
shoreline pump right next to it, & it pumps it out nearly dry. Tried multiple positions, to no avail.

At this point I'm just gonna install a cheap mechanical switch & hope for the best.
It's just a little 14 foot utility boat, no actual bilge, pretty sure it'll be fine.

Heading up to the Manitowish chain in another week or so, hopefully I won't actually need it.


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