Johnson Bilge Pump

[skongolf]

I have a johnson model 3250 (500 gph) bilge pump that uses a replaceable cartridge in my Maxum i/o. I am pretty sure it does not work anymore as when I hit the bilge switch I hear a noise but nothing comes out of the bilge port and there is definately water in the bilge. Basically one day I forgot to turn it off when I trailered the boat and ran it for about an hour dry. Anyway, they make the replaceable cartridges still and it seem pretty straight forward except for the wiring. It looks like the new cartridge comes with new wire which will be a pain to run under the engine. Also it looks like the wires will go straight to the battery, so how does the switch operate the bilge pump. Maybe I am overlooking something, but I just want to know how to do the replacement correctly before I do it. Thanks.

 

[Bob's Garage]

Re: Johnson Bilge Pump

It will be a pain, for sure.

There are 2 wires on this model pump; the black is the ground and connects directly to either the battery or a ground "buss bar".

The brown wire is the positive lead and connects to a brown (maybe) wire coming from the switch. There is another wire going from the switch to a fuse, or circuit breaker, then to either a positive "buss bar", or the battery.

If you have a float switch, then there will be another brown wire attached to the pump wire that goes to the float and then the power source. (This may be what you are seeing, as otherwise the pump would run continuously.)

Make sure the connections are water tight, protected with heat shrink, and secured above catastrophic (flooded) water level. You might use plug-in butt connectors to make replacement easier in the future as you will probably be doing this again, down the road.

This seems to me to be the most logical setup, but there are always alternative methods of installation.

 

[smokeonthewater]

Re: Johnson Bilge Pump

ok now hold on a sec here.... before you go "repairing" it you need to find out what is wrong..... check the hose for blockage kinks or cuts... then check for clogged inlet to the pump... pull the cartridge out and look at the impeller.... see if it is intact and un damaged and check that it spins freely and silently by hand.... turn the pump on and verify that it spins fast......

It is VERY VERY unlikely that you damaged the pump by running it dry for an hour..... I've forgotten them for weeks before with no damage:redface:

If indeed you do have to replace it then trace the wires that are already there until you find the splices... snip them off and use heat shrink cold crimp butt connectors to splice the new ones in and tie the connections up above the likely bilge water level

 

[seabob4]

Re: Johnson Bilge Pump

Smoke is correct, you can run a bilge pump forever and it won't burn up, it will just kill the batt.

Here's a basic drawing showing how the float is wired in and operates the pump, as well as how the switch on the dash works...

We use Rule pumps and float switches, the 2 leads coming off the float are gray. Yours may be brown...

 

[skongolf]

Re: Johnson Bilge Pump

Smoke is correct, you can run a bilge pump forever and it won't burn up, it will just kill the batt.

Here's a basic drawing showing how the float is wired in and operates the pump, as well as how the switch on the dash works...

We use Rule pumps and float switches, the 2 leads coming off the float are gray. Yours may be brown...

Thanks for the diagram, it deffinately helps. Mine does not have a float swith, just the bilge pump alone. I will deffinately pull it and check it, but what a pain to get to. This may be something worth paying a mechanic to do. Gonna have to pull the s-belt to get at it with both hands. I hope.

 

[seabob4]

Re: Johnson Bilge Pump

Bilge pumps in I/O boats is definitely a BIG PITA! If there is room enough to get it forward of the engine pulleys, they're not so bad. But then they are too far forward to clear water in the aft end of the bilge, which is where water naturally collects...

I would HIGHLY recommend installing a float, this will take care of you when you're not on the boat, even if she lives on a trailer. Rain water, you know...I use Rule-a-Matics, they'll work with a Johnson pump.

 

[skongolf]

Re: Johnson Bilge Pump

If i take the belt off I can get at it alot easier that will be for sure. Running the new wire may be a different story though. Looking through the manual for a mercruiser motor it makes it lok kind of confusing for taking the belt off. Hopefully its not.