Bilge pumps run every 20 seconds

[yager97]

Like the title states, my bilge pumps run every 20 seconds, not 2.5 minutes like they are supposed to. This caused me to arrive at my boat after a week of no use in its slip, with dead batteries, twice. Is there any settings on the bilge pump I'm not aware of, or should I just replace the two pumps? Anyone else have this issue? Boat is a 2004 nautique sv-211 team. Thanks

[shawndoggy]

I would want to know why you are getting so much water in the bilge that the pumps come on so frequently. you are addressing the symptom not the disease.

[jhersey29]

Take it over to the lift and get a much water out as possible or put it on the trailer to get the bilge dry. Get the boat in the water and see if you have a good leak. Pop up the motor cover and see if the pump is running due to water level. The float in the pump could be stuck in a high position with no water in the boat it may come on check it when dry

Areas that should be looked at for a starter:
Drive Shaft Stuffing Box
Rudder Stuffing Box
A hole in an exhaust pipe

[yager97]

Bilge pumps are rule fully automatic pumps. They perform test runs to "check" if there is water every two and a half minutes by design, no float switch. The issue isn't water, they will run every 20 seconds while bilge is dry on the trailer. It's kind of a stupid design, reminds me of the Simpsons episode when homer designs an alarm that goes off all the time to tell you everything is ok

[shawndoggy]

Oh in that case why not just replace with an attwood Sahara bilge pump which works on a float switch and should be available in the boat aisle at your local walmart for around $50?

[DanielC]

The bilge pumps do not sense water. They do not have a float.
What they check is the RPM of the impeller. When they are pumping water, the drag if the water slows the pump impeller down, and the pump stays on.
This works good until sludge and gunk from the bilge gets inside the pump housing. If there is crud dragging the speed of the pump impeller down, the pump thinks it is moving water and stays on.

Do both pumps stay on and go off at the same time? They should not, because the "decision" on if the pump is to run or not, is determined by each pump. They should not influence each other, they should be independent.

The pumps do share wiring to a point. They are controlled by one switch, or relay in the control box that the touch pads in the dash are connected to, but obvoiusly, a separate pair of wires goes to each pump.

I used to work at a Correct Craft dealership. I had to find a problem where the circuit breaker for the bilge pumps kept tripping, even though the front pump still worked. After a lot of work, I found both the ground and the hot wire for the rear pump was clamped under one of the washers on a bolt that held the rear hatch hinge. This created a short circuit, tripping the breaker.

Pull the pumps, and check for gunk inside them. You can clean then by using a mild solvent, like paint thinner on a Q-tip, partially. I do not remember if the pump impeller housing can be opened up to clean it completely. You might also be able to get some gunk out with a strong detergent, in very hot water. Anything to loosten up the goo inside the pump.

Unfortunately, Lead acid batteries do not like to be completely discharged. Doing so reduces the capacity of the battery to hold a charge. You might need to replace the battery, if your battery is old, and has been completely discharged a few times by the bilge pump.

And all the above advise about checking for water leaks into the hull still apply. Prop shaft, rudder shaft, any through hull fittings, including those on the wake shaping plate. Mounting bolts for the platform. Any through hull fittings for engine cooling, and the ballast system. Check the bolts holding the rudder port. Check for leakage at the screws that hold the tracking fins on the boat. Check for leakage if you have a paddle wheel sensor for speed control going through the hull.

[jhersey29]

Thanks DanielC great info I will add this to the knowledge bank. I did want to add for other users reading this forum for other boats that many bilge pumps do have float switches so be sure what type of bilge pump your trying to diagnose.

[shag]

Awesome info DanielC! There's a reason why he has over 2500 posts...

[yager97]

DanielC thanks a bunch, awesome and thorough info. I was planning to change out the batteries as well I was told that once they discharge fully, they no longer hold a charge very well. Anyone have any recommendations for batteries I should use to replace?

[nyryan2001]

folks are confusing frequency with duration.

Daniel's reply is super helpful, but doesnt adress the FREQUENCY issue the OP is having of the too frquent bilge check cycles for water.

His remarks would directly related to the DURATION of each bilge cycle..if the blades were heavy, it'd run longer during the checks etc etc, 100% agreed... not the frequency, as it clicks on and runs for 2-3 seconds, then clicks back off. No indication of load on the pump impellor.

Yager- when it cycles every 20 seconds... how long does the pump run during those checks? just a few seconds?

[yager97]

Correct, just a few seconds. My issue is with frequency not duration

[nyryan2001]

ok, so these pumps have a timer that cycles them on and off... at a specified 2 min or whatever intervals.

Yours has chosen to reduce that interval, something in the circuitry...likely just need to be replaced.

I would definitly clean the blades as Andrew suggested just to ensure thats not it.... but likely you will need to replace. If your application requires you to have a pump that stays on... and you are not on a charge and worried about battery life.... I'd consider one of the water sensing ones, or one with a float switch.

[kend]

Was anything ever resolved with this? I'm out of town keeping my boat on the lake and when I set it to"bildge" it runs a water check every 30sec (no water so it turns off quick). I'm worried that my battery will be gone tomorrow. I thought it was every 15min that it was supposed to check. Sounds like the rear pump only.

[scottb7]

Do both of them really come on every 20 seconds? That seems odd that both would become defective in the same way.

P.S. If you want to leave your pumps on but worry about draining the battery then just pick either battery 1 or 2 on the switch not both.

[vision]

Mine runs every few minutes. Leave them in for weeks. Batteries fine.