Tachometer problems

[zubol]

Hello guys,

I have bought one of this tachometers

(http://greatlakesskipper.com/produc...-outboard-only-oversized-boat-tachometer.html), connected to my engine (Force 85 HP 88') on 20 pole and unfortunately it does not work...
Any idea what to do?

Thank you for any advice...

 

[TMALEGA]

Re: Tachometer problems

Start with simple things check for a good power and ground. Then check to make sure the wire going from the motor to the signal post on the back of the tach isnt corroded anywhere and/or broken/pinched. Make sure it is actually connected to the block back at the motor. I had a bad rectifier that was causing some issues and from what i read if that goes out then it will affect the tach. So that may be worth looking into.

 

[zubol]

Re: Tachometer problems

Do you know what voltage should be sent to tachometer by the engine?
Can I test it by the Multimeter tester?
Can I test tachometer without starting the engine?

 

[TMALEGA]

Re: Tachometer problems

Not sure on the voltage. I know i tested mine with a volt meter setting it for ohms and checked for continuity throughout the wire. I know its a pulse signal so it isnt a set voltage i believe. Someone told me if i had a led type test light i could try that for testing to ensure signal was getting there. But if the wire is solid with the continuity test then the signal should be getting to it. Check the rectifier though.

 

[roscoe]

Re: Tachometer problems

cannot test the tach without a signal, therefore the engine must be running

 

[fucawi]

Re: Tachometer problems

set your meter to AC volts and check you have a reading on the input terminal to the tacho ..its the frequency of the signal that gives the rpm not the actual voltage..... engine must be running.

 

[droach77]

Re: Tachometer problems

set your meter to AC volts and check you have a reading on the input terminal to the tacho ..its the frequency of the signal that gives the rpm not the actual voltage..... engine must be running.

Don't you mean DC volts fucawi.

 

[Bighornbob]

Re: Tachometer problems

droach77--on my 1996 Force 120 (and I think on a lot of other outboards also) I'm pretty sure the voltage comes in to the regulator/rectifier from the stator as AC current. Then the rectifier changes it to DC current, and sends the rpm signal to the tach and the recharge DC volts to the volt meter and battery. So, the input to the rectifier would be AC, but on to the tach and volt meter it would be DC. At least that's how I think mine works.

 

[zubol]

Re: Tachometer problems

Guys I checked the connection between Tach and engine, also power and ground - everything is OK. Do you have any other ideas?

 

[jerryjerry05]

Re: Tachometer problems

Is there a dial on the back of the tach? See pic.If so try turning it when the motor is running.
What color is the lead to the tach? Should be grey(I think) You need to jumper power
(purple wire) and a ground to the terminals.Make sure they are connected right.J

 

[zubol]

Re: Tachometer problems

Yes I have dial on the back and it's set to 4 (20 pole). Tach cable from engine is purple and it's connected to signal on the tachometer. Also, ground to GRN and power to power.

No grey cable at all....

 

[pnwboat]

Re: Tachometer problems

Have you checked your rectifier to make sure it's good?

 

[Barnacle_Bill]

Re: Tachometer problems

The input to the tach is AC not DC. The pulse is taken off before it goes thru the rectifier. Like others said, test the rectifier.

 

[goodtimesfishing]

Re: Tachometer problems

friend of mine is having issue with that same tach, can't seem to get it to work. His old one worked but just trying to have matching gauges on his dash. We are trying to figure out how to tell if the tach is bad or something else? How can everyone test the tach to make sure it is working properly?

 

[zubol]

Re: Tachometer problems

Maybe it's a stupid question, but how to test rectifier?

 

[pnwboat]

Re: Tachometer problems

You may find this helpful.

http://www.youtube.com/watch?v=dqkT6hF0O3E

 

[zubol]

Re: Tachometer problems

thanks for the link. Where I can find this rectifier?

 

[pnwboat]

Re: Tachometer problems

Most electronic component supply stores carry a generic version that looks exactly like the original at a fraction of the OEM cost.

http://cgi.ebay.com/Bridge-Rectifier-35-Amp-1000-Volts-/260791809168?pt=LH_DefaultDomain_0&hash=item3cb8673490

 

[zubol]

Re: Tachometer problems

but where is it on the engine?

 

[pnwboat]

Re: Tachometer problems

If you have a 1988 85HP motor, it is mounted right next to the starter. There should be 5 wires connected to it. Two Green with Yellow stripe wires coming out from under the flywheel, This is the AC output from the stator, one black wire that is the ground, one red wire that is the DC output and either a gray or purple wire that goes to one of the same terminals that the Green/Yellow wires are attached to. This is the tach signal wire.

http://www.youtube.com/watch?v=pAV14aj_DT0

http://www.youtube.com/watch?v=ThX0_E9x1mc

http://www.youtube.com/watch?v=R2ngCNezp8Q