Alt pushing voltage 14.2 at battery but dash and PP say 11v what's wrong?

[CUE99T]

Guys, I've replaced the belts now and I still seem to have a voltage display problem.

My PP has stopped working and I think it's down to the voltage not being directed to the PP gauge and to the dash gauge either as it shows 11 too.....

so where do I start diagnosing the fault and what's possibly the cause as its ok over the battery.

thanks in advance.

paul

[Chexi]

Check your alternator belt tension. It is probably slipping.

[NautiqueJeff]

What year is the boat? If it is an older one, they were famous for having too small of a ground wire running from the dash, and that caused all sorts of voltage problems as the boats aged.

[CUE99T]

Belts just replaced today and is tight.

I have a 2001 SAN with GT40 engine.

i think the ground sounds more like it, how do I go about checking up to the dash, does it come from the battery, and go into the engine harness or go straight up to the dash??


Also is the PP going to get a ground from the same wire going up from the back of the boat?

any wiring diagrams etc i could see to give me a trace?

cheers
paul.

[jeepn]

When I added the second battery in my 92, I added another ground wire since my wiring for the second battery was running past the dash anyway. The volotage meter always read wrong, and most of my gauges would go wonky when I turned on the lights before I did this, all my gauges work correctly now.

[t3e871]

Where does the ground wire attach under the dash? and at the other end?

[Mikeski]

My 98 Ski Nautique is even worse 14v at the battery 10V at the PP. The factory has #10 wire running from the motor to the dash off a 50A breaker, scary! I will be replacing that #10 and associated ground with a #6 wire that will run from the alternator, to the motor, to the dash. This is the way it should have been done at the factory on day 1.

[t3e871]

I am getting the full 12.8v (with motor off) from the battery at the (+) and (-) of the breaker box, but it goes down to 10-11v at the v gauge on the dash and at the 12v receptacles. So if I increase the size of the wires going to the breaker box, that may help increase the voltage at the dash and 12v receptacles?

[CUE99T]

So had dealer fit the new belt and it sheared off again within 5mins but we think it might have been too tight, so moved it about half an inch and it seemed to have done the trick. Full days driving and no belt issue.

Perfect pass seems buggered though, Gary from PP reckons its broken as it won't store boat hours or any settings but does start up all ok and reads all the usual settings but won't store a thing....anyone any ideas on that one??

Cheers for all the other tips and info on the wiring etc. Maybe a winter job when we fix the heater which has blown a matrix. Apparently we need to get the dash out for that one!!!!