Tachometer

[Mavric]

Please need help with my tachometer on my boat , ive only just wired it up all wires correct the problem is the needle moves on its own up passed 8000 rpm whether the engine is running or not yes you read right even with the engine not running and can only get it back to zero if i disconnect the earth lead from it any help would be appreciated never had a gauge move on its own without the engine running it the needle only moves slowly to passed 8000 rpm .

Help please .

 

[superheat6k]

Can you list the connections and what is providing the revs input - alternator, sensor probe, etc

 

[Mavric]

It's got + , - and signal mate if that's what your on about and as far as im aware my charge system and rectifier are ok ive connected it to the grey wire and also bypassed it by connecting straight to the yellow stator wire and once the gauge has power to it the needle starts to move on its own whether the engine is running or not ive even direct wired the gauge to the battery poss and negative it just seems very strange as i didn't think the needle would move until the engine was running but the needle goes past 8000 rpm and stays there until i disconnect the earth from it .

 

[VicS]

It's got + , - and signal mate if that's what your on about and as far as im aware my charge system and rectifier are ok ive connected it to the grey wire and also bypassed it by connecting straight to the yellow stator wire and once the gauge has power to it the needle starts to move on its own whether the engine is running or not ive even direct wired the gauge to the battery poss and negative it just seems very strange as i didn't think the needle would move until the engine was running but the needle goes past 8000 rpm and stays there until i disconnect the earth from it .

Tach on outboard engine take it ? If not what engine ?

I would suggest that if the gauge reads anything other than zero with just the positive and negative connected, and no engine running that might generate interference that the gauge could pick up, Its faulty.

But one thing you might check is what happens if you ground the signal wire instead of connecting it to the grey wire from the regulator.

 

[Mavric]

It's on a mariner 50hp 2 stroke 4 cylinder outboard mate

 

[Mavric]

The yellow signal wire and the grey wire are connected to the same pole on the rectifier mate so could you explain mate as i don't understand , because forgive me if im wrong if i earth the yellow wire from the stator surely it would blow something because doesn't it carry a charge voltage ?

 

[Mavric]

It slowly creeps up to 8000 rpm without the engine running with the signal wire connected and the power and earth connected i can only get it to zero if i take the earth off the gauge .

 

[Mavric]

No one else got any help ?

 

[VicS]

The yellow signal wire and the grey wire are connected to the same pole on the rectifier mate so could you explain mate as i don't understand , because forgive me if im wrong if i earth the yellow wire from the stator surely it would blow something because doesn't it carry a charge voltage ?

No thats not what I meant.

Forget it. It probably would not have told us anything useful anyway

 

[Mavric]

" No need to get shirty matey i asked for help not attitude " .

I know exactly what you meant , you meant the grey wire from my tach instead of connecting it to the signal wire from my outboard to earth it to an earth point instead .

 

[Mavric]

Incidentally i checked the charge system and it barges my battery so given all what ive said before and this any ideas what's wrong with my tach ?.