Tach Wiring Question

[brstock]

Trying to get my tach to work. I have an 89 Classic Fifty 45hp. I've checked that it has power when the key is turned on and will return to zero when it gets power. It had the grey wire connected to the pulse terminal. There is power at the grey wire when I connect the grey and black to the volt meter but when I turn the motor over it doesn't seem to 'pulse'.

Is the grey wire the correct wire for the pulse and is there a way to verify that it is 'pulsing'? I would prefer not purchasing a new tach if I don't need one since they are fairly expensive.

 

[achris]

Re: Tach Wiring Question

Trying to get my tach to work. I have an 89 Classic Fifty 45hp. I've checked that it has power when the key is turned on and will return to zero when it gets power. It had the grey wire connected to the pulse terminal. There is power at the grey wire when I connect the grey and black to the volt meter but when I turn the motor over it doesn't seem to 'pulse'.

Is the grey wire the correct wire for the pulse and is there a way to verify that it is 'pulsing'? I would prefer not purchasing a new tach if I don't need one since they are fairly expensive.

Sounds like you've got a blown rectifier.... One of these...

http://www.mercruiserparts.com/showSpecialPicture.asp?pn=816770T

 

[brstock]

Re: Tach Wiring Question

Based on tests I've found it looks like the rectifier is bad. I'll order a new one. In the mean time can I hook the tach directly to the strator wire or will/could that cause damage? I would like to get these carbs set so I can take it to the water and adjust. Thanks for everyone's help.

 

[achris]

Re: Tach Wiring Question

I'd wait until you have the new rectifier....

 

[saumon]

Re: Tach Wiring Question

If you haven't ordered it yet, you should consider replacing that rectifier with the newer rectifier/regulator combo from CDI. Not sure if they're available for your particular engine...

 

[achris]

Re: Tach Wiring Question

Found the CDI rectifier here at iBoats....

http://www.iboats.com/mall/partfind...gd_poid=334699&gd_row=35&**********=303057630

Chris......

 

[brstock]

Re: Tach Wiring Question

So you recommend CDI over other brands? I'll assume so and order that one. The extra 10 bucks is worth it if people trust the brand. Thanks everyone!

 

[brstock]

Re: Tach Wiring Question

Thanks, it was the rectifier. When I got the new one I compared the continuity and they didn't act the same. Works like a charm now....now on to wiring the backlight into my navigational light switch. Someone before me had really chopped up the accessory wiring on this boat. A simple 2 ft piece of straight wire was spliced together with 4 different pieces of wire end to end. Thank god they didn't touch the harnes wiring. Thanks everyone!