tach and rectifier

[CMF]

I just bought a 83 Hydrostream Voyager w/ a 88 Mariner 200 and have ran into a few small problems.

tach wasn't working so I started troubleshooting.
There are two posts that have yellow wires on the rectifier. The original tach was connected to the one on top. I tried a car tach on both and found that only the one on the bottom will trigger the car tach. The original tach will not work on either. AC voltage is 2-3 on top post, 9-10 on the bottom. DC voltage while running is only 11.97. Am I correct in assuming that a new tach and rectifier should do the trick?

Something else I noted...the car tach works without the postive terminal connected, but jumps a few hundred rpm when it's connected.

Thanks for any help you guys can give.

[T-REX]

Tha tach should work on either yeller wire...U may try a new wire from rectifier to tach terminal...I had a couple harnesses that had bad wires in them...I think it wuz around wher tha harness bends ever time ya turn tha motor...New wire solved problem...But Your problem soundz like a rectifier...fergit tha car tach!!!...REX:cool:

[O/B Dude]

Do you have a manual for your motor? It gives the procedure to ohm the rectifier. Easy to do. If it ohms OK, its the tach or like T-Rex said, the harness. Car tach may move when connected but wont read correctly. Be sure not to connect it to the power terminal.

[CMF]

Thanks for the suggestions.
I should have given a little more info. I didn't get the manual with it. I just figured out what year it was by the serial number, 0B332649. I'll be ordering a book or two for it soon.
I have removed the tach from the panel and I'm using new test wires, but I'll check out the harness before I'm done.
I'm going to check the thing with a meter right now.

It just seems wierd hat the tach and the recitifier went out at once. Could the wiring on the back of the tach have shorted out and caused the rectifier to go bad? The wiring was pretty nasty behind there before I replaced it all.

Thanks again

[CMF]

I don't know what the numbers should be on my motor.

The rectifier tested at 1770 K Ohms. This seems high.

The two yellow wires tested at .8 Ohms. ???