150HP 1990 tach connection and tach function

[rhodyboater]

Hello:

New engine for me.

The tach does not work. I suspect a wiring issue and want to check the continuity of the wire from the tach to the engine (green wire?).

I cannot find where the tach wire is on the engine. The seloc manual says controlbox but is very unclear. Is there a connection at the controlbox at the helm (gearshift/throttle)? I guess the neutral safety switch is there.

Also, any tips to see if the tach is working. When the engine runs there is no current at the tach.

Thanks

[jb123]

you should have 3 flat harnesses going to motor, just find the tach harness and test

[boats.net]

green tach signal wire is inside main 10 pin harness and connects to stator or CDI unit on engine depending on model of motor.

[rhodyboater]

150 yamaha tach checking at helm

I am still puzzled after checkiing for tach hookup at engine.

How do I check for voltage at the tach itself? What should it be and should it change with RPM?


Is there a tach hookup at the engine? It is a electronic ignition engine. 1990 150HP yamaha.

Thanks!

[jazzman44]

i have had the same problem i fixed mine after checking my wiring i found it to be an earth wire problem. im not saying yours is but its worth checking out

[rhodyboater]

Tach Issues remain!

Hi Again:

I checked the engine again, still puzzled.

1) The two small gauge wires on the back of the tach are green and black, the green goes to a green wire but the black goes to a yellow one. The other wires are for a light and idiot lights. I believe yellow is switched ON power. I would think this black wire should go to a ground?

2) I cannot find a green wire at the engine itself to check for continuity, any suggestions where?

3) How can I check for current/signal at the tach itself with the engine running? Can i hook up a car tach?

4) How do I check to see if the engine alternator is working?

5) Is there a tach hookup at the engine (electronic ignition).

Thanks!!

M