Volvo penta md22l tachometer issue, possibly key connection

[jmuir1]

Hi
Problems ongoing with tachometer not working. I ve checked all connections and also removed alternater to get it checked in a professional workshop. They couldn't find anything up with it? Last year it was variable and needle on tach. would drop and alarm would sound but engine didn't skip a beat. Still on the hard and have put alternater back on a now and on starting the engine it very occassionly works then drops to zero. I've wiggled the key and think there is an issue there as all warning lights on panel do not always light up on first turn point of key. I think from memory they should all light up and then go off once engine is running...correct me if I am wrong. Is there anything I should check further. The charging light would occassionly stay illuminated on starting but goes off if I gently move key slightly, again making me think there is an issue with the key connection, would this affect tachometer too?
Any views ideas appreciated,
John

 

[VicS]

Hi
Problems ongoing with tachometer not working. I ve checked all connections and also removed alternater to get it checked in a professional workshop. They couldn't find anything up with it? Last year it was variable and needle on tach. would drop and alarm would sound but engine didn't skip a beat. Still on the hard and have put alternater back on a now and on starting the engine it very occassionly works then drops to zero. I've wiggled the key and think there is an issue there as all warning lights on panel do not always light up on first turn point of key. I think from memory they should all light up and then go off once engine is running...correct me if I am wrong. Is there anything I should check further. The charging light would occassionly stay illuminated on starting but goes off if I gently move key slightly, again making me think there is an issue with the key connection, would this affect tachometer too?
Any views ideas appreciated,
John

Your owners manual will tell you how the various warning lights and audible alarm should function, including when the ignition is first switched on. If you have mislaid your copy you can download one from http://www.volvopenta.com/marineleisure/en-en/for-owners/your-engine/manuals---handbooks.html Just enter MD22L into the "product designation" box

It sounds to me as though your ignition switch may be faulty. If you look at the wiring diagram you will see that the power for the tacho and for the warning light module both come from the same terminal of the switch. Worth checking the connections on that terminal though before finally condemning the switch.

I guess you do not have temperature gauge, pressure gauge or voltmeter or those would not work either

 

[jmuir1]

thanks for your reply and advice. Will check that terminal and wiring diagram.
John

 

[peteK]

I had a similar problem with the tachometer dropping to zero and it was dirty carbon brushes.

 

[VicS]

I had a similar problem with the tachometer dropping to zero and it was dirty carbon brushes.

hopefully that is not the OP's problem as he has had the alternator checked.