Scared me...Smoke in the Cabin out to Sea-gctid390163

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Did a little early morning fishing this moring with a friend about 7 miles offshore. Catching a few baracudas having fun, and my friend says he caught a wiff of what smells like an electrical fire. That got my attention, and then I caught the same wiff, and began sniffing around down in the cabin. I turned off the battery switch still smelled it and then saw a little smoke haze in the cabin. But, with the batteries off?

Oh! The bildge pump is the only thing not going through the battery switch. Pulled up the little hatch in te floor, and the front bildge pump was melting and smoking. It is on a float switch and there is no water in the bilge. I immediately cut the wires which cured the problem, but why would a bilge pump, with the helm switch off, and no water to move the float switch fry like that?

That scared me...Wouldnt it be on a fuse in case of some sort of dead short problem? I have not investigated all the wiring to see where the failure was.

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OK, first things first. In this case, a fuse doesn't sound like it would help you at least to this point. The plastic housing of the bilge pump was getting too hot at the bearing holes, and creating heat and smoke. The motor was drawing the normal amount of current for the supply, and until the motor seizes you have no idea if the circuit would exceed a rated fuse, say 5 amps.

Next, was it a combined float switch/pump, or was the float separate? If the float switch was combined with the pump housing, the float may have been caught on some debris in the housing making the float stick up, and run the pump. If it were a separate float switch, it could be stuck with some debris, you don't mention if the arm of the float was up or not.

Third, what about the bilge pump switch on the dash? Usually there are two ways to run the pump, one in auto mode which is not fused, and one in manual mode from a 'fwd bilge' switch on the dash. Was the dash switch on, and forgotten? Are you sure? If so, then check the switch by putting a meter on the wires at the pump where you cut it, and operate the switch. Check to see that the voltage goes off. I've seen switches fail in the on mode.

Last, you generally want all circuits on the boat fused. Most auto bilge pump circuits have a fuse in a rubber sealed pack right downstream from the + terminal of the batt. It could be a barrel type of fuse(typical in boats from the 80s) or it could be a spade type with a rubber housing around it. If it's not fused off the battery, sometimes it is fused at the fuse block, you'll have to get the book out to know where it is.

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Reading your response makes me suspect the dash switch. The float switch is seperate, and was in the down position. The helm switch was also off, and yes I double checked that, but last night, I did hit the bilge pump switch just to test it, and everything seemed fine. I was worried that maybe I left the switch on, but it was in the off position when I cut the wires. I spent the night on the boat last night and did not notice anything running in the bilge, but then I am not sure if I would have noticed it it were stuck on. It seems it would either have to be a faulty helm switch, staying on even in the off position, or the same for the float switch.

If a pump was left running dry, how long would it take to melt it?

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dpoelstra wrote:
If a pump was left running dry, how long would it take to melt it?

it depends on the pump quality. I have seen a small cheap one starting to smell after ~10 minutes.

The one in my last boat, a 1978 US made quality pump I could run all day without any damage but I fear that buying such a pump today would show that they are made from unafordium. As more they are made in China as less I trust them.Korea and Taiwan are usually better.

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Juergen is exactly right. You can't find a pump with lifetime sealed ball bearings, and windings that will run 100% duty cycle dry anymore. Maybe if you looked at offshore products there might be such a product but for inshore or lake boats of our caliber, the product isn't avail. We demand low price, and along wit that comes products that are disposable.

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Not the first bad switch if that what it is. I am thinking of working on a whole new dash panel and guage cluster and replace it all. I have to tap on one of my guages to get it to work too.