89 90HP Johnson. Where is the Tach lead?

[Joe421]

My tachometer works sporaticly, and never for more then a few seconds. I've tested the tach and it works fine. I went as far a buying a manual to look at the wiring diagram but it doesn't list a tach lead for my particular year and model. Does anyone have any advice on how to get my tach working again?<br /><br />Thanks in advance.

 

[solidwaste75]

Re: 89 90HP Johnson. Where is the Tach lead?

I dont know youre engine exatly but on my 85 hp johnson the tach lead is the gray wire. It is the only gray wire on the engine..

 

[solidwaste75]

Re: 89 90HP Johnson. Where is the Tach lead?

check the terminal block the gray wire should be for tach..It goes from there to the conector at youre throtle control consul..They may have bypassed the control consol like in mine and ran it directly from the tach to the terminal block..In my manuel its the only gray wire on youre engine..

 

[solidwaste75]

Re: 89 90HP Johnson. Where is the Tach lead?

OH Yea make sure to check all grounds to make sure they are still tight mine had lossened causing my problem..

 

[Joe421]

Re: 89 90HP Johnson. Where is the Tach lead?

Originally posted by Joe421:<br /> My tachometer works sporaticly, and never for more then a few seconds. I've tested the tach and it works fine. I went as far a buying a manual to look at the wiring diagram but it doesn't list a tach lead for my particular year and model. Does anyone have any advice on how to get my tach working again?<br /><br />Thanks in advance.

Still can't figure it out. I checked the gray wire and it doesn't read any voltage. Is this the problem? If so, where does the gray wire originate? I checked for voltage on the connection block that has the clip on cover. Anybody?

 

[KYHunter]

Re: 89 90HP Johnson. Where is the Tach lead?

I just hooked up my new tach and it works great. I'm no expert , but the tach gets signal pulses from the charge system . I'm not sure how this would show up on a meter. The grey wire is connected to a jumper thats between two yellow wires one of which has a stripe. The grey wire as far as I understand originates at the terminal strip . It is the sender wire from alternator to tach. If your motor is running and the grey wire is tied to one of the yellow wires your tach should work. I did a continuity test from terminal strip to control box to be sure my wire was still ok.<br /> If you want to test run a wire from terminal strip to tach and see if it works . If it does then your grey wire is probably bad.<br /> Good -luck,<br /> KYHunter

 

[Joe421]

Re: 89 90HP Johnson. Where is the Tach lead?

Originally posted by KYHunter:<br /> I just hooked up my new tach and it works great. I'm no expert , but the tach gets signal pulses from the charge system . I'm not sure how this would show up on a meter. The grey wire is connected to a jumper thats between two yellow wires one of which has a stripe. The grey wire as far as I understand originates at the terminal strip . It is the sender wire from alternator to tach. If your motor is running and the grey wire is tied to one of the yellow wires your tach should work. I did a continuity test from terminal strip to control box to be sure my wire was still ok.<br /> If you want to test run a wire from terminal strip to tach and see if it works . If it does then your grey wire is probably bad.<br /> Good -luck,<br /> KYHunter

I checked by running a wire from the connection block at the gray wire straight to the tach and I get nothing.

 

[KYHunter]

Re: 89 90HP Johnson. Where is the Tach lead?

Do you have a good ground? My old tach only had a sender , grnd. and power to light connections, I dont know what yours has . The light didn't have to be connected for tach to work. I would connect a direct grnd. and the sender directly to the output wires from alt. This way you'd know for sure that tach. is no good.