Tach Troubleshooting

[metriccrescentwrench]

Bought a tach on ebay a little while ago but it won't work in my boat. I've got a 1981 Johnson 90 HP, by the way.

First off, I did have a bad rectifier but that has been replaced and I'm now getting around 14.8 volts.

I connected the tach to a signal generator and found that it will work when the incoming AC signal is higher than about 7 volts (as measured on a Fluke dmm). Anything less than that and it sits on zero. Can anyone tell me if that seems reasonable?

 

[jtexas]

Re: Tach Troubleshooting

Teleflex says it needs at leads 4 VAC, at least there's one point of reference.

 

[metriccrescentwrench]

Re: Tach Troubleshooting

Thanks, that gives me something to go by. Sounds like my tach is at least in the ballpark as far as sensitivity, so now I start looking at wiring.

 

[Laddies]

Re: Tach Troubleshooting

Heres some good info
http://ww2.tflx.com/obtachtrad.html