Wayward Volvo Tacho needle !!

[crazy4557]

Can anyone shed any light on why one tacho immediately shoots round to the 5000 revs position once I turn on the ignition and stays there? I have checked all the contacts on the alternator and the back of the tacho and they are fine. Would faulty internals of the alternator be a reason. /forums/images/graemlins/confused.gif
The engines are Volvo AD41B's. Any clues please folks?

 

[Anthony]

try swapping the tachos over (presuming they are the same) and see if the fault follow the tacho or stay with teh engine.

Anthony

 

[DavidJ]

Following on from Anthonys' logic, swap over the alternations. I'd put a little bit of money that the problem follows the alternator.
Maybe if you don't want the hassle of changing the alternators you may consider just changing the "W" alternator terminal connection from one to the other (you will need a wiring extension lash up).
I've never done it and I would prefer some concurrence from other forumites before doing this.

 

[volvopaul]

Hi take it you have 2 boats then? or is this a project.
I would check the contacts, has the boat been stood for a while, it may be damp if so remove the taco put in the airing cupboard or like me place on a t towel on top of the boiler in the house for a few days, it did the trick for me.

Failing that, unplug the multiplug on the engine, spray with a suitable electrical cleaner, check the alternator.

If the engine loom connector cables are long enough swap them from one engine to the other.

 

[PAULSTEWART]

Sorry, can't help with your problem, but you've just reminded me of probs with my tachos on the same engines. The ones on the fb work fine, but the ones in the cabin only work when they feel like it..which isn't very often! Anybody got any ideas as to cause??? Any help greatly appreciated...

 

[DAKA]

Never had this fault but just a thought if it is a new to you boat I would be tempted to check voltages.

you may have 12v / 24v system running side by side ?????