Battery and Bilge pump question????

[Fiat4Fun]

Howdy,
I have a 1986 Mercruiser 5.7, and I noticed that my batteries are draining when I don't turn the switch to off. Everything is turned off, so I was thinking that the alternator may have a bad diode. Is there a easy check for that while the alternator is in the boat? I hate to pull it out, and it charges the batteries just fine when it is running.

Also, my bilge pump is acting strange, it will turn on ( as it is automatic) and light comes on on the dash, I can hear it, but nothing comes out. Sometimes it will pump just fine, other times it just turns on and nothing happens. I did check to see if there is water in the bilge, and there is enough to turn it on. I replaced over five years ago, so not sure how long these last. Any insight to that would be appreciated.

 

[UncleWillie]

I would get the bilge pump issue iron out first.
If the pump is running and not moving water something is wrong.

An even bigger issue is, why is there water in the bilge?
Unless there is a definite reason for water in the boat (Rain?), the bilge should be bone dry.
Also the bilge should be clean. Leaves or dirt blocking the pump will stop the water flow and kill the battery.

 

[roscoe]

Does your bilge pump have its own built in switch, or an external float switch?

These newer ones with their own switch inside have been know to have problems.

 

[Fiat4Fun]

I have a Johnson Ultima pump that is five years old, and it is an automatic pump. The switch is inside. It kicked on, but it did not pump anything out.
What would be the best bilge pump to replace the old one with????
Thanks
Bob

 

[UncleWillie]

If the pump is turning it should pump. If it is humming, it may just be stopped up.
Remove the pump and inspect it before you start throwing money at a pump you did not really need to replace.

Most pumps will need about 3 inches of water to start pumping. That is one heck of a lot of water.
They will not come anywhere close to pumping the bilge dry.
You may still have 1 to 2 inches remaining when it shuts down.
Stick a garden hose in there to see if when you get enough water it will pump.

While you're at it, clean the bilge and drain, sponge, and towel the bilge bone dry.
Then figure out how the water got in there in the first place.

If you have a leaking bellows, you will ruin your Gimbel Bearing and U-Joints.
Water in the bilge will eventually rot the stringers. If you have a leak, find it.