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Tachometer not playing ball - TMD22

David Cummane
 

The needle on the tacho for my Volvo Penta TMD22 goes to the far side of the dial on turning the key but does not return to zero/rev count.

Periodically the needle shows a rev count after the engine has been running for some time.

Behind the panel there are two black wires connected to a female pin which looks like it should be attached to a male pin, however there are no obvious male pins available.  Picture below.

Has anyone had a similar problem or can anyone shed some light?

Many thanks

David Cummane
Ker Marie, SM#101 

 

It could be your 12 volt alternator....the tach gets its signal from the Alternator. Sounds like the alternator is NOT exciting. Probable cause is a faulty relay or loose wire to the relay.

--
CW Bill Rouse Amel Yacht Owners School
Address: 720 Winnie, Galveston Island, Texas 77550 
   


On Tue, Oct 15, 2019 at 4:51 AM David Cummane via Groups.Io <davidcummane=mac.com@groups.io> wrote:
The needle on the tacho for my Volvo Penta TMD22 goes to the far side of the dial on turning the key but does not return to zero/rev count.

Periodically the needle shows a rev count after the engine has been running for some time.

Behind the panel there are two black wires connected to a female pin which looks like it should be attached to a male pin, however there are no obvious male pins available.  Picture below.

Has anyone had a similar problem or can anyone shed some light?

Many thanks

David Cummane
Ker Marie, SM#101 

Arlo
 

My tach on my Perkins showed similiar behavior and I traced it back to a corroded connector on the alternator that goes back to the tach. Check the sensor voltage on the back of the tach when the engine is running. I believe the voltage for the tach sensor on my perkins was around 6 or 8 volts when working properly. I cleaned the alternator spades and replaced the female connector and all is well now.