1987 85 Force outbaord Tach issue

[powerboater44]

I recenlty had to replace a bad rectifier. This caused the voltage to all of my guages to exceed 18-20 volts. The Tachometer (which was not working properly anyway) burned up, along with the voltmeter and fuel guages. T replaced the rectifier with that 090-1 voltage regulator that I found from another thread. I now have a steady 14.2 volts even at max rpm. I replaced the tach (20 pole) and the voltmeter. The tach works great at lower rpm, say idle to about 2500. I will then notice it drops to around 300 rpm. The weird thing is.... If I switch on my running lights, it will correct the problem. I have checked all of the ground wires to all of the guages, and they all look good. Any suggestions?

 

[pnwboat]

Re: 1987 85 Force outbaord Tach issue

Try disconnecting the other gauges one by one to see if that has any affect. If that doesn't have any affect, I'd start looking at the wiring to the stator or the stator itself.

P.S. Did you replace the Fuel gauge too?

 

[john from md]

Re: 1987 85 Force outbaord Tach issue

Powerboater,

I have noticed this problem occurs whenever you change from a rectifier to a regulator. Usually, your tach will work at certain rpms and jump around or read low at others.

When I connect an induction type of tach, the readings are fine and I verified that the readings when stable are accurate. The tach gets its signal from the stator and the only connection involving the rectifier/regulator is that the purple wire is joined to a stator yellow/green wire at the rectifier terminal. Changing to a regulator should not make a difference but for some reason it does.

We need an electrical engineer to tell us why this is happening. Other than a loose connection, which I have checked several times, I cannot see why adding the regulator causes the tach to act up.

Regards,

John