Removal of bilge float switch

[convergent]

I have a Mayfair 26012 bilge pump float switch that doesn't seem to be working. It is switching, and there is voltage through when its up, but for some reason the pump won't come on. It seems to be dropping the voltage down to about 9.5 volts for some reason, so I guess its shot.

Its in a very hard spot to get to and so once I take the screws out I'm sure it will be difficult to get them back... and near impossible to change their location. The switch seems to be attached to the bottom of the hull with two philips machine screws. Do I have to worry about leaks or anything with screws going right into the hull floor? The screws are kind of hidden by the hose in the picture, but you can see that's its screwed right to the hull. Anyone know if I can get a replacement switch that will work in the same holes?

This one looks similar to it... http://www.iboats.com/Johnson-AS888...0220779--**********.128576380--view_id.341201

I have just never messed with screws in the hull of a fiberglass boat before and don't want to introduce a leak inadvertently. I know the screws don't go all the way through the hull since they don't come through the bottom of the boat, but I have no idea how thick the hull is. If I need to relocate the holes, what's the safest way to do this?

 

[Rocky_Road]

Re: Removal of bilge float switch

Are you sure that your bilge pump is operational? Does it cycle on from the helm switch?

The reason that I ask, is that a float switch is a pretty simple item...like a wall switch, power off or power on. My guess is that your pump may be the actual culprit.

Happy boating!

 

[sasto]

Re: Removal of bilge float switch

Appears to me to be mounted to a block and not the actual hull.

 

[seabob4]

Re: Removal of bilge float switch

I kinda lean with Rocky here. When you rotate the auto-test knob on the float to turn on the bilge pump, you should have minimal voltage drop. Your pump may have the shaft bound up. Pull it out and see if the shaft/impeller rotates freely...

 

[convergent]

Re: Removal of bilge float switch

Thanks for the suggestions guys. Let me respond to everything.

- The pump works fine with the panel switch flipped on, or if I jump it directly to the battery.
- I have disconnected the float switch and checked the resistance when engaging it. Initially it was jumping all over the place so I toggled it abruptly several dozen times and it settled down to a consistent resistance when engaged... forget how many ohms it was. I think it was about 250.
- If I jumper the switch straight from the battery to the pump it won't come on. If I short the two switch leads it does.
- Without anything attached to the switch but the battery, I get only about 9.5V when its tripped instead of 12.5V going into it.

Given the debugging, I'm pretty convinced that the switch is bad.

Regarding the screws, I stuck my head way in there and the two screws I am pretty sure go straight into the hull. There isn't a block of wood under it or anything. There are other things attached to the hull that way too.. tie-downs all over the place are. I don't know a lot about hulls, so its possible that there is something layered on top of it, but it can't be too think because the drain plug and the other 3 holes for the live well on the transom are all a few inches away from where the float is attached and I can visualize things from outside the boat. So these screws must be pretty short? I tried to take a picture of the screws but I can't get my iPhone down in there and get a shot... I may break out the DSLR and give it a shot.

 

[Stachi]

Re: Removal of bilge float switch

buy a new float switch , 250 ohms is resistance and that means it is not conducting the correct voltage...tie that in with only 9.5 volts and that means the switch is no longer functional, clean ALL electrical contacts in the system (postive and negative) use the original mounting screws in the same area of the hull that the previous float switch was mounted...you should be fine after this. Good luck bro...

 

[Rocky_Road]

Re: Removal of bilge float switch

Thanks for the suggestions guys. Let me respond to everything.

- The pump works fine with the panel switch flipped on, or if I jump it directly to the battery.
- I have disconnected the float switch and checked the resistance when engaging it. Initially it was jumping all over the place so I toggled it abruptly several dozen times and it settled down to a consistent resistance when engaged... forget how many ohms it was. I think it was about 250.
- If I jumper the switch straight from the battery to the pump it won't come on. If I short the two switch leads it does.
- Without anything attached to the switch but the battery, I get only about 9.5V when its tripped instead of 12.5V going into it.

Given the debugging, I'm pretty convinced that the switch is bad.

Regarding the screws, I stuck my head way in there and the two screws I am pretty sure go straight into the hull. There isn't a block of wood under it or anything. There are other things attached to the hull that way too.. tie-downs all over the place are. I don't know a lot about hulls, so its possible that there is something layered on top of it, but it can't be too think because the drain plug and the other 3 holes for the live well on the transom are all a few inches away from where the float is attached and I can visualize things from outside the boat. So these screws must be pretty short? I tried to take a picture of the screws but I can't get my iPhone down in there and get a shot... I may break out the DSLR and give it a shot.

Sounds like you are headed in the right direction...replace the switch.

If you can get an exact replacement, then you know that the current screws will be fine. Or you can do what I did: clean the area real well with brake cleaner...scuff the area with some coarse sandpaper...and use 3M 4200 adhesive to mount the switch.

Happy boating!

 

[sasto]

Re: Removal of bilge float switch

I think you will find the keel is filled and glassed over, depending on your boat. If your drain is level within the bilge area and you have a couple inches on the outboard transom this may be the case. If it were me I would use a Rule float switch. Nothing personal about Mayfair but I have trusted my life to the Rule.