Marine Ac/Dc

We received the following email from Jack about a problem that he is having with his Aqua Patio pontoon:

I have an on again off again electrical problem.

The boat is pontoon, Aqua Patio.  When boat was purchased the live well in rear had a factory problem.  the live well leaked over the switch mechanism; the boat yard rewired the system to a console accessory swich.  It worked for a few years but I am convinced it is a ground problem.

As soon as the motor receives current it works at a very low speed (not enough to pump).  The motor works when placed across the battery directly.  The voltage is 12 volts at the motor when turned on.  When the motor is hooked up and tested it may or may not work for a minute.  When motor is disconnected and the voltage remeasured the volt reading is somewhere between 2-6 volts.  I have voltage at the console but the same senario occurs when I connect and reconnect motor.

The boat is still out of the water so it is easier to track wiring.  It is so many splices because of the rewire that I hate to start cutting wires to isolate. The port and starboard rear courtesy lites I think do not work which are connected in the circuit.  Cell phone or portable courtesy lite receptacles are in the circuit (have never used but don’t think they work). The old switches that were part of the courtesy/live well circuits are disconnected and by-passed.

The new wiring to the console is blue to ground, the hot is brown.  The new circuit is connected to the black in 2-3 different places, of course, difficult places to get to, so dismantling is necessary.

Can you give me a starting point since it is difficult to trac this by yourself? Is there an isolation proceedure that can be done without cutting all the wiring?

Thanks.

Jack,

This is a common occurrence on boats that are made of metal.  Godfrey Marine, like every other pontoon builder, does not use the metal framework on the boat as a ground.  This helps prevent stray current corrosion (galvanic corrosion), but causes strange ground problems like the one you are having.

Another problem that occurs on pontoon boats is when the boat wiring harness is not properly secured to the underside of the deck.  Even if properly secured, wires can be damaged even under normal use, e.g., the wires could be caught by the trailer or perhaps damaged during a “stunt docking” maneuver.  Whatever the cause, the boat wiring may now be able to make intermittent contact with the metal framework of the boat.  While the resistance is high enough to not trip the breaker or blow the fuse, it can still cause extremely low voltage readings under load conditions.

The best solution to your problem is to run two new wires to your live well pump.  Disconnect the existing wires.  Connect a new ground wire from the negative of the live well pump (usually black wire) to your battery negative or a negative buss near the battery.  Connect a new live well power wire from the positive of the live well pump (usually brown) to the accessory switch on your console.  I would recommend using at least a 16AWG good quality tinned copper boat wire.

This is my simplest solution to your situation.

Good luck,

Kevin