1981 70 hp tach not working

[bowman316]

I just installed a tach last year on my rude, and i needed a new rectirier before it would work. It worked fine for a year, but this september it just stopped working. It would jump around, and not move a whole lot. SOmetimes it would reset back to 0 when you turn the key, but then settle back to 2,000 rpms or so, when i know the engine is at 4,000.

Do you think the rectifier could be bad again? or just a wire came loose from the engine? I hooked the tach up from a port comming out of the throttle control box. I jiggled those wires, and not much happened. I have not charged the batteries in months(I have 2), and they start the motor fine. this is a 1981 engine btw.

 

[bowman316]

Re: 1981 70 hp tach not working

so i know that the engine is charging the battery's, because i killed both batteries with the troling motor one day. (I'm retarded) and had to pull start my engine. It started right up, and kept running. When I had a bad rectifier, I got a jump start, and it died after it was running. This did not happen this time

 

[bktheking]

Re: 1981 70 hp tach not working

Check your wiring at the tach and at the rectifier.

 

[R.Johnson]

Re: 1981 70 hp tach not working

Unplug the tach at the control box. With a volt meter, test between the gray, and black wire at the control box. It should show about 9 volts. Then test the red wire out of the rectifier. Shold be around 14 volt's, or above battery voltage.