1996 force 40 new tachometer not working

[Chris35rt]

Today I installed a new faria tach cause the old one was 20 years old an stopped working now the new one I can't seem to get to work. I did get to work briefly but that was it. I do know its getting 12 volts to the tach since the light works and tach goes needle moves to zero when ignition is turned to on. Here is what i have checked so far. At the voltage regulator the two yellow wire coming out of the stator I'm getting about 16 volts AC and the red wire coming out of the voltage regulator I'm getting 14.5 volts DC so i am guessing all is good with the stator and charging system. What i'm not sure is how to check the gray wire coming out of the voltage regulator other than continuity and that checked good from the tach back to where it hooks into the VR. Could it still be and issue with the voltage regulator or something else I should check? Based on the instruction that came with the tach i set the switch to 5 which is for a 12 poles. Thanks for any help you can give me.

Chris

 

[gm280]

:welcome: Chris35ft to iboats...

Sounds like you have everything connected correctly except you didn't mention anything about the tach ground to the engine. The light works so that part is grounded or the light wouldn't work. But do you have a good ground between the engine and the tach? Also, is the gray wire connected to the input side of the voltage regulator or the output side? It needs to be to the stator side being the AC side of the voltage regulator so you are reading the AC pulses. Then you can switch the little pulse switch on the back of the tach back and forth a few times to make sure it is making good clean connection. If that doesn't work, you could have a bad tach. JMHO

 

[Chris35rt]

Thanks for the welcome. Far as ground I'm thinking the VR is grounded to the engine maybe? It doesn't have a specific wire coming out of it going to ground. it's the original VR that came on the motor it is a metal box with what appears to be filled with clear epoxy. It has two yellow wires a red wire and the gray wire coming out of it.

 

[Chris35rt]

No Title

Looks like this one

 

[gm280]

Looks like this one

Well then it looks like you have it all wired correctly. Maybe sand the mounting hole areas to make certain it is getting a good ground, but beyond that, there isn't much more you can do. If the pulses are not coming out of the voltage rectifier module via teh gray wire, you may have to purchase another one. But it still could be your tach as well. Do you have an old tach that still works to use as a trouble shooting guide? It doesn't have to read properly. But if it does read anything then that would at least rule out the voltage rectified itself. Try your AC voltage meter to see if you can read any AC voltage from the voltage rectifier on teh gray wire. The gray wire outputs pulses and your AC meter may read something as well. I have a frequency setting on my Fluke and it can read such things. Worth a try. JMHO

 

[Chris35rt]

Think it's going to be the VR. Cleaned it and the bolts up really well put it all back on cranked motor and still no tach working. Hooked the meter up to it and verified the system was charging which it was and then switched to AC and checked the grey wire nothing. I left it hooked up for few minutes and then suddenly the meter starting reading some current hooked the wires up and the tach was working, it worked for about five minutes then the tach stopped working went back and check the grey wire and there was no current. Nope i don't have an old tach that works. Sound like the VR after all?

 

[gm280]

Think it's going to be the VR. Cleaned it and the bolts up really well put it all back on cranked motor and still no tach working. Hooked the meter up to it and verified the system was charging which it was and then switched to AC and checked the grey wire nothing. I left it hooked up for few minutes and then suddenly the meter starting reading some current hooked the wires up and the tach was working, it worked for about five minutes then the tach stopped working went back and check the grey wire and there was no current. Nope i don't have an old tach that works. Sound like the VR after all?

CHris35rt, Before culling the voltage regulator, try tapping into another input AC wire to see if that works. Odd that it is charging good but the tach's gray wire is intermittent. It now sounds like the gray tach output wire is possible broken internally in the voltage regulator. If you could tap into one of the stator wires that goes to the voltage regulator, it could work. JMHO.

 

[Chris35rt]

Yep i can try that. I'm headed to the lake tomorrow I will get that a try.

 

[Chris35rt]

Quick up update the rain stopped so I was able to go out to the boat and try the jumper and yep that worked!! The jumper I made it not the same size as the gray its smaller diameter will that be ok? Also seeing how that worked I could just leave it hooked up to the stator wire? I really appreciate all the help you have given me. Thank you!

Chris

 

[gm280]

Quick up update the rain stopped so I was able to go out to the boat and try the jumper and yep that worked!! The jumper I made it not the same size as the gray its smaller diameter will that be ok? Also seeing how that worked I could just leave it hooked up to the stator wire? I really appreciate all the help you have given me. Thank you!

Chris

Yes on both questions. You can leave it connected to another stator output wire, but make certain it is insulated and secure so it doesn't brush against anything moving. And yes you can use a smaller gauge wire for that circuit. It is merely using the AC cycles and not very much current. So now you know your voltage regulator is the problem. But unless you just want to replace it, you can run with your new setup. Just keep it in mine that you jumped the gray wire down the road is anything else crops up. You could even dig into the clear epoxy like materail and fix the problem wire inside and then pour some epoxy back in to reseal it. But all those ideas are just me thinking out loud. JMHO