Tach issues

snookhooked

Petty Officer 2nd Class
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Aug 19, 2008
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159
Ive been trying to hook up the tach but no luck. I was told the gray wire but when hooked up nothing. did a test light and it shows nothing. there is power going into it but not either way from the gray wire. its a 150 Evinrude soit fire motor. theres only 3 wires from it. one goes to a power source on panel and the ground is hooked but the other wire which Im thinking would be the sensor wire is the one loose and thats the one I hooked up to the gray wire. ists near the ignition switch. maybe the gray wire isnt the right one? any help would be greatful. Thanks
 

Chris1956

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Mar 25, 2004
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28,131
Re: Tach issues

Grey wire is normally the tach signal wire. Make sure the tach has +12VDC (purple wire) and -12VDC(Black wire). Now do a continuity test on the grey wire, from the tach to the voltage requlator (or rectifier). If you have continity, it could be that the VR is bad.
 

snookhooked

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Re: Tach issues

that's where it confusing me. its not hooked to any purple wire. the purple wire I have is on the ignition look like a key ring type bungee if that makes any sense. Im going to do some more pics of where it leads and the the send wire has been hooked up not to the ignition and its always hot but the ignition wire has been hanging loose. I hooked it up to the gray wire but nothing. I'm putting a pic of the tach. it has no name so maybe some will know who makes it? I think someone ran something wrong to tell you my opinion and I just think if I can get it wired right, it should work. its almost like they hooked it to a switch and I think it would be hooked directly and the light wire would be hooked to the panel lights. sounds right? the pictures arent the best.sorry
HPIM0349.jpg
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Chris1956

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28,131
Re: Tach issues

The gauge looks to be a Tiempo. The tach must have +12V, ground and Tach signal to function. Purple is the usual color of the +12V source, and should power all the gauges. Do you have a fuel gauge that works? Piggyback the black and purple wires from that to the Tach. You should have a small AC voltage on the tach sender wire, only when the motor is running. if the motor is off, the tach signal wire should be dead, unless you have a bad voltage regulator or rectifier.

What year is that motor?
 

snookhooked

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159
Re: Tach issues

Unfortunately I don't have a gas gauge to go off. this tach has a tendency to stick, so I'm guess its more than likely bad anyway. it didn't have a name so I couldn't at least help by name. the harness to the switch has purple one and a gray wire that is hanging loose. I was told that was for the tach but tried it nothing and it shows no power. what I need to do is take a pic of the panel where all the wires are and go from there. at least you would see and maybe give you a better idea of what I have. when getting the boat, it had a 140 Evinrude about 84/85 and I changed that motor to this 1992 Evinrude Spit Fire E150ELENC. everything hooked up fine. on my ignition switch it has a purple wires and if what you are saying thats my tach hook up, that wont be bad. let this rain stop and I will get you some pics. Thanks so much
 

snookhooked

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Re: Tach issues with pics

Re: Tach issues with pics

ok, I have some pics now. you will notice that the purple wires go to the temp light and choke. the blue wire that was on the ignition that went to the tach and the green wire (ground) was to a switch. Im thinking it was to the ground side so they didnt have to run it that far. you will see that the gray wire is loose.(I took a pic of it) I have tested this wire both with the ignition on and off but either way showed no power. Evinrude does call for gray for tach. now how would test to see where my problem can be? this motor was told was rebuilt so I would tend to think that my problem is either in the wiring or tach. the power I did have to the tach was the blue one and like I said that was from the ignition. does any of this make sense?
HPIM0351.jpg
HPIM0352.jpg
HPIM0352.jpg
HPIM0354.jpg
 

Chris1956

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28,131
Re: Tach issues

Snook, It is hard to decipher that spagetti from a photo. You want +12V in the ign pole of the tach. That will come from the ign switch, accessory pole. Normally they would run the hot light and choke on the accessory voltage. You want -12V (ground) on the gnd pole of the tach.

Now find the wire that goes to the stator wire and route it to the sender pole of the tach. This wire should connect to one of the yellow stator wires, upstream of the voltage rectifier or rectifier (whichever you have).
 

Silvertip

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Sep 22, 2003
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28,771
Re: Tach issues

Whoever did the wiring on the cigarette lighter plug did that backwards as well. The metal shell of the socket is ground and the center terminal is +12 volts. If the red wire is actually ground, the wrong wire color is used. If the center terminal is actually +12 volts, then the wrong wire color was used there as well. If sensitive electronics are plugged into this and polarity is reversed you risk sending it to electronics heaven. This wiring needs a serious re-do.
 

snookhooked

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Re: Tach issues

I sure agree on the wiring being a spaghetti mess. I'm trying to figure it out and get it all running right. unfortunately Mako doesn't have any wiring diagrams out there and I cant really understand the Evinrude book that I bought for the motor as far as the wiring. the cigarette light is capped closed and has been that way for so long that its rusted beyond even trying to use it if you wanted to. I wouldn't dream of putting any electronics threw them. it has a block that I use for my radio which has both ground and hot sides. Im going to replace that whole panel with a real piece of teak and IM going to update the switches in the long run. I just need to fully understand all the wiring when it come to replacement so that I can have everything where it should be and right. believe it or not everything working but the tach part but that's due to finding the right way too kook up. is there any place where I could get something readable to where I can know where every wire should be? I'm sure that is a stupid question on my part but I sure cant afford someone to come in and redue it either. Thanks. what you have told me gives me a idea of what to look for and what I should be hooked up too.
 
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Silvertip

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Sep 22, 2003
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28,771
Re: Tach issues

There are a couple of generic wiring diagrams at the very top of this forum. Boat wiring at the console is pretty standard. In your situation I would rip it out and start over. No need to figure out what you have that way. You simply add new following the diagram.
 

snookhooked

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Re: Tach issues

Ok, this is what I have done and what its doing. I hooked it all up like said but the ing side shows power when key switch in on. the light works on gauge but still nothing on the sensor side. I put a test light and it shows nothing. thats the gray wire that goes to the sensor if I remember right?wiring.lol what a lovely thing to try and trouble shoot. as to the cigarette light. its useless in terms of ever using it. it was caped off and has been on there so long that its rusted beyond even trying to fix it but I will replace it here shortly but if I am correct, the sides are the ground and the center is positive right? Thanks for all the help.
 

snookhooked

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Messages
159
Re: Tach issues still no tach

Re: Tach issues still no tach

OK, I put a new cigarette light in and wired it the correct way. I'm still having no luck with the tach. when I turn the ignition on, I do have power on one side of the tach(ign side) but nothing on the sensor side. to troubleshoot this is what I need to know. follow the gray wire back to the motor and do what from there? how would I go about doing a test to see what may be wrong?
 

Chris1956

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28,131
Re: Tach issues

Snook, The tach signal is the AC voltage from the stator. The grey wire will either be directly connected to one of the yellow stator wires at the rectifier or connected to the AC side of the voltage regulator, depending on what motor you have. You can connect it to the yellow stator wire for testing your tach function. If the tach is good, perhaps the regulator or rectifier is bad.
 

snookhooked

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Aug 19, 2008
Messages
159
Re: Tach issues

Chris, it a 92 150hp Evinrude. I will look for what you said and see what happens. I just thought once the motor was running, I could see if it worked or not. which it didn't so its learning how to trouble shoot it and then I should find my problems. Thanks. I should have listed the motor. sorry about that,
 
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