tachometer and rectifier/regulator mystery

[salty_dawg2]

I have a '98 Johnson (90hp, optical ignition)with the multi-gauge display. Tach recently quit, the lights all OK. Replaced rectifier/regulator, tach briefly registered while cranking, then quit again. Tach reads at zero, rather than floating up to 1000 or any other reading when cranking or completely off. No voltmeter, but haven't had any battery problems or voltage drops on electronics either. I'm baffled. Does anyone out there have any ideas?

 

[12Footer]

Re: tachometer and rectifier/regulator mystery

I be thinkin it's in the connections to the tach or the tach itself. If it were the pickup, the engine would not run iether.<br />the fact that it bounces just indicates the tach has power, but does it's counter chip still count? Your guess is as good as mine.<br />It is possably the A/D converter chip (wherever it is).<br />How many wires does your tach have?

 

[clanton]

Re: tachometer and rectifier/regulator mystery

You have to check voltage on gray lead from regulator, with peak reading meter.VRO2 is connected to same circuit. 2 columns in service manual.