blown fuse

san dimas

Petty Officer 1st Class
Joined
Jan 20, 2012
Messages
369
After a rain my boat blows a 20 amp fuse attached to the main battery and I lose my gauges and fish finder. If I replace the fuse everything is ok for the rest of the day. One time I replaced the fuse on the lake and everything was fine until I trailed to another lake. After I put the boat in the water the fuse was blown again. The boat is aluminum and I'm thinking that maybe the problem is the one of the pumps for the bilge or live well. Maybe the water moves to the bilge and shorts out. What puzzles me is that I don't turn anything on or off when this fuse blows. Any ideas? The only thing I do is raise the motor up and down.
 

WrenchHead

Petty Officer 2nd Class
Joined
Feb 15, 2009
Messages
120
You say after a rain the fuse blows. To troubleshoot -- when the boat is dry and parked and the fuse is good put some water in the bilge and then see if the fuse blows. If it does blow then the problem is water in the bilge shorting out some electrical piece of equipment. If the fuse doesn't blow then you will have to start isolating other pieces of equipment. Good luck.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
If you boat in fresh water,even salt, highly unlikely water is causing fuse to blow. Look to wires rubbing against the hull.
 

san dimas

Petty Officer 1st Class
Joined
Jan 20, 2012
Messages
369
Thanks guys. I'll put some water in the bilge and see if I can find the problem. I'll also see if I can find a bare wire.
 

DeepBlue2010

Lieutenant
Joined
Aug 19, 2010
Messages
1,304
What type of fuse is it?
What is this fuse connected to?
Was it replaced before and if so, are you sure it was replaced with the correct type? Not all fuses are equal and some of them are designed to stand a very short overshot of current drawn by inductive loads (almost all motors are). If you had a slow burning fuse on the trim tilt pump and it was replaced by the wrong kind of fuse, you will blow the fuse every time the pump is running
 
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