tach not working

[johnnybay]

hi ,got a rinker 192 2005 , now the tach is not working ,the hour clock is still ok , does any one konw what this could be , any way to test it before i start to spend money on a new one?

 

[Greg Mrozinski]

Re: tach not working

Johnny,

Basically it could be one of four things - no ground at gauge, no power at gauge, no signal at gauge, bad gauge. So check the first three and if everything is okay then it's a bad gauge. To check the ground, do a continuity (resistance) check between the gauge ground post and a known good ground source. There should be almost no resistance (like 0.1 ohms). If ground is good then next check the voltage between the gauge ground post and the ignition (power) post with the key turned on. There should be at least 12 volts showing. If that checks out okay then check the signal wire by doing a continuity check between the gauge signal lug and the signal source on the engine (usually the stator for outboards or ignition coil for I/Os). Again there should be almost no resistance. If all these are good then replace your gauge.

 

[Silvertip]

Re: tach not working

The gauge has a built in hour meter and it is working so +12 volts and ground are ok. The problem is that there is probably no tach signal. But since we have no idea what engine powers this boat, can't help with that.

 

[johnnybay]

Re: tach not working

hi ,thanks for that , engine in the boat is a volvo penta 4.3 if any one can help

 

[Silvertip]

Re: tach not working

The tach signal comes from the engine ignition system. You will need the schematic from the drive service manual to identify which wire it is and the wire color. However, you can also determine that by looking at the back of the tach. +12 volt and ground connections should be obvious since you will see those two colors on every instrument. The non-common color on the tach will be the tach wire. Check that wire for continuity from the tach to the engine. If this is a digital tach, and the send wire is ok, then there is a possibility that the tach is bad.

 

[johnnybay]

Re: tach not working

hi ,the colours are grey ,purpel , black , blue , they all seem to read 12 volt ,so you think it should be the tach then?
also just before it was winterized the tach was a bit erattic , then ok , then it when like that again when we layed it up for the winter , but now its totally still.
many thanks

 

[Greg Mrozinski]

Re: tach not working

hi ,the colours are grey ,purpel , black , blue , they all seem to read 12 volt ,so you think it should be the tach then?
also just before it was winterized the tach was a bit erattic , then ok , then it when like that again when we layed it up for the winter , but now its totally still.
many thanks

Purple is ignition power; black is ground; gray is the tach signal wire and the blue is the power lead for the gauge light.

Sorry I missed the piece about the hour meter working in my previous response.

 

[johnnybay]

Re: tach not working

thanks ,so it looks like a new tach then ,will have to order 1 up
thanks for the help.

 

[Silvertip]

Re: tach not working

If you measured 12 volts on all those lines then yu did something wrong. Black is ground and will not measure 12 volts. The tach signal is also not 12 volts. Only the light and the +12 volt line shold read 12 volts.