Tach won't work above 4000-4200 rpms.

[mike91695]

I have a 1985 Johnson 120hp outboard mounted to a 1985 Skeeter bass boat. My tach cuts out and goes back to 0 when the engine goes above 4200 rpms. When I throttle back down below 4200 rpms it comes back on??? I have replaced the regulator last year because it was not charging. I have also tested the stator and it tests perfect. Now it charges at 13-13.5 volts and 7 amps. I have replaced the tach and ran a test wire from the gray wire on the regulator to the tach with the same result. The tach used to work intermittently with the old regulator. Has anyone had this problem before, or have any ideas what could be wrong? I have tried adjusting the pulse setting on the tachs, but they only work right on the one setting. Thanks

 

[hydra23]

Re: Tach won't work above 4000-4200 rpms.

Mike;
I experienced the issue, in my case was a loose ground connection behind the starter assembly. (1996 Johnson 175 ocean runner). I trace all the wires to their terminal starting from the stator, reg/rec half way thru the process I found the culprit a loose ground connection that was making my tachometer recycle at above 3,500 rpm`s (vibration under way) was shorting the circuit. It would not happen while trolling or at idle speed. One of the two loose ground cables was directly connected to the reg/rec wiring harness. If all your test came out good look for a loose ground connection. It save me $150.00 for a reg/rec.
H

 

[mike91695]

Re: Tach won't work above 4000-4200 rpms.

Hydra23, I did check that ground because I put new brushes in my starter at the same time. But thanks anyways. Anybody else have any ideas???

 

[jwellcraft]

Re: Tach won't work above 4000-4200 rpms.

I had the same problem with my 1995 150 and it was the voltage regulator but double check all of your connections and make sure you don't have any chaffed wires anywhere under the console which is grounding out the tach and maybe try a known good working tach from someone but most likely it's your VR.

I have a 1985 Johnson 120hp outboard mounted to a 1985 Skeeter bass boat. My tach cuts out and goes back to 0 when the engine goes above 4200 rpms. When I throttle back down below 4200 rpms it comes back on??? I have replaced the regulator last year because it was not charging. I have also tested the stator and it tests perfect. Now it charges at 13-13.5 volts and 7 amps. I have replaced the tach and ran a test wire from the gray wire on the regulator to the tach with the same result. The tach used to work intermittently with the old regulator. Has anyone had this problem before, or have any ideas what could be wrong? I have tried adjusting the pulse setting on the tachs, but they only work right on the one setting. Thanks