For some reason last time I went out in my boat the livewell stopped working. The livewell pump, a johnson 1000 gph cartrridge model is located in the bilge. It is turned on byna switch at the helm. I pulled the pump and hooked it up to a small 12v 7ah gel cell. The pump made a few sounds like it wanted to turn but wouldn't. I figured the pump must be bad so I bought a new pump. I put the new pump in and it fired up like normal. I oniy ran it for 5 to 10 seconds. I tested it again a couple hours later and it ran fine. So I came back to test it again the next day. It started up like normal but I quicky heard the pump slow down and speed up. That got worse and then it just stopped and would not run. I cut the wires and with a multimeter was able to see voltage swings on the line. To fix this I cut out the only splice could see in the line. I figure my next step is to run new wires from the switch in the helm to the bilge, where the pump is located. Is there anything else I should try to diagnose this? It's weird because it ran fine the first couple times I tried it then went on the fritz.

Sounds like a poor connection, likely heating-up after running a short while. Run a new wire, solder connections if you have the ability.

With a mm connected to the wire in place of the pump and the switch at the helm turned on the mm shows a stable 12.4v. With a pump and the multimeter connected at the same point and the pump turned on by the switch at the helm, the mm shows 10.4v. I think this voltage is too low to run the pump.

Does this still point to replacing the wire?

I was going to run a new positive wire but the odd thing is, if I look at the outgoing + at the switch that is used for the pump it is brown with black strip. The wire at the pump is only brown. That's got me a little puzzled. The outgoing + on the switch must go through something else to turn into straight brown.

Sheesh. I just left the pump and mm connected with the switch turned on. The voltage comes up initially at about 10.4v the the voltage starts bouncing around and the pump makes a thumping sound. The mm goes to 0v, around 8v, and then 10.4v. The pump does not spin at all but it is getting power. At least I don't hear any spinning. Could it be a bad pump? I also hooked the pump up to the house battery directly and the pump did not run. I did not check the voltage at the pump for this.

As said, sounds like connection is breaking-down somewhere (losing voltage). Replacing the wire/connectors shouldn't be a major deal.

If you like, connect the pump directly to a 12v power source (like a battery charger, just read other post and saw where you connected to battery) and see how the pump runs. If it's fine, you've isolated the problem.

Wiring gets spliced/replaced over the years. Color coding sometimes no longer applies 100%.

FYI 12.4V is about 80% charge.






Depending on what else is connected to this (start?) battery, are you having any related issues from anything powered from this battery?

Possible to have a bad battery, even though it shows 12+ v, but not enough to actually power something.

Guys, I am just puzzled. I got out to the boat this morning, disconnected the new Johnson pump and put a rule 360 GPH pump in it's place. The rule was meant to go in a bait bucket so I was just using it for testing. I then flipped the switch at the helm and the rule pump turned on and ran fine for a couple minutes till I turned it off. The rule was hooked up using the alligator cables and not crimped. I then put the Johnson pump back in place with alligator clips and tried it. It now works too. The voltage at the pump drops to 12.2v. It is about 12.v4 when measured at the battery. The odd thing is, last night after developing problems I did hook the Johnson pump directly up to a 12v battery, it would not run. I also noticed that last night when the Johnson pump started developing issues it was also heating up. The voltage was also fluctuating wildly. The voltage was 100% stable today.

This is exactly what happened last time where when I put the Johnson in it worked. I came out to the boat a couple times in the following couple days and turned the pump on for 5 to 10 seconds to make sure it would fire up. About the second or thrid time I did that the voltage starting fluctuating and the pump started acting up, and then just quit.

Is hot running to ground on that leg?

A pumps love is not like a squares

Thanks for your help KB7DX. I have added some info in bold above.

It just occurred to me that the butt connectors I am using are the heat shrink type but I bought them on Amazon. They are Chinese and not 3M or another reputable brand. It seems very unlikely but maybe those butt connectors are introducing loss in the line...

I felt the main body of the pump heating up and I'm not 100% sure but I think both wires were heating up as well.

Thanks for the input osprey21!

If you're running it for any period of time out of water, it probably would heat up.

I ran it for maybe 30 to 45 seconds. Not sure if that would heat it up.

Thanks for the info. I'm going to have to do a lot of homework before taking on that project (if I feel confident in doing it). I might just head to west marine and grab some anchor btt connectors and heat shrink, just to be sure I don't have an issue there.