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tach not working on 1998 90 hp oceanpro

J

jasontd101

New member
This is my first post on the forums and appreciate any help anyone can provide. My 90 HP ocenapro Evinrude I purchased recently has an issue with the tach. The tach does not work at all. I have already replaced the voltage regulator so I know that is not the issue (the new regulators do not have a purple wire but was told that is normal). The tach has the 4 warning lights and I know the hot engine light and low oil light work as I have had both go off since I had the boat. Hot engine light was clogged thermostats and low oil was the oil tank was low (I use my vro). So with that said when I turn the ignition key on before starting the engine it goes through the test and make a loud warning sound and then all 4 warning lights run through their test sequence properly and the tack needle very slightly moves (hard to see but it twitches a hair). I pulled the plug off the back of the tach and put my voltage meter on the black (-) and grey (+) wires and I get nothing if engine is running or not. I did check the plug from the voltage regulator as well and all the wires and plug connection look very good.

What should I do next? Should I run an ohm test from the black and grey wires on the plug running to the back of the tech? When the boat is not running should I get some ohm reading so I know the wire is not sliced somewhere? Is there anything besides a sliced wire at this point that would cause no voltage on the grey and black wires on the plug that connects to the tach? From what I read the tach runs off the voltage regulator but I just swapped that and still have the same issue as before changing it out with a new one. What else could cause the tach not to operate at all? I have only run a voltage test on the plug that connects to the back of the tach at this time and as stated no voltage when off or running.

Thanks for any help that you can provide :)
 
Some voltmeters will not read the voltage pulses coming from rectifier,go to " HOW TO "check a marine tach on internet
 
johnnygjr said:
Some voltmeters will not read the voltage pulses coming from rectifier,go to " HOW TO "check a marine tach on internet
Click to expand...

I did test to see if I got any reading from the voltage reg plug that has just the grey wire coming off of it since the purple wire is no longer used and it does read I think about 4 volts so that would confirm my multi-meter can read a signal then correct? If so what are the best steps to figure out where the issue is based on my initial post?
 
If the charging system is working it is either in the wiring or the tach. Try switching the pulse switch on the back of the tach and see if it starts reading on a different setting. Is it getting voltage to the + and - terminals with the key on?
 
kimcrwbr1 said:
Your engine has the five wire regulator here is the test procedure for the regulator. Use a ohm meter to test the tach circuit
http://www.cdielectronics.com/wp-content/uploads/2013/09/IS-193-6048.pdf
Click to expand...

Thxs for the pdf link. The regulator is brand new and the tach did not work before and after changing the regulator. I see the last line of the pdf says "Tachometer Circuit: Check the ohms resistance between the Grey wire and engine ground. You should read approximately 10K (10,000) ohms. Grey to Red, and Grey to the Yellow wires should be a high reading, usually in the M range. "

Should I unplug the plug on the back of the tach and on the plug itself check the ohms on the back and grey wire inputs? That should tell me of the wire has been damaged / cut correct?

Also when the engine is running or in the on position and not running I get no voltage on the grey and black inputs on the tach plug- just fyi as well. Thanks everyone for your help! :)
 
********************
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.


Normally the Gray wire leading from the tachometer is attached at the terminal strip to another Gray wire which leads from the water cooled voltage regulator/rectifier...... remove the gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.
 
joereeves said:
********************
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).
Click to expand...

THXS joereeves, I did read your post that you pasted here previously and just not sure still. So I did some more tests today after everyone's suggestions. Here is what I found.

1) Voltage regulator is band new (like less than 2 weeks old) and if I test the grey wire coming off of it, it reads a few volts (cant remember exactly how many as I tested this last week but I think around 4 volts)

2) I tested with my multi-meter today on the plug that plugs into the back of the tach black and grey pins with engine off in on position but not running 0 volts and when it is running i get 0.01 volts.

3) Purple and black wire I get 14 volts

4) If I check ohms on the plug that plugs into the back of the tach using the back and grey pins on the plug I get 00.8 at 200 dial on ohms check

Anyone know what my problem is with a brand new voltage reg that had a non working tach before and after changing it and with the above multi-meter readings? Thxs again for all the input!!!!!!!!! :)
 
joereeves said:
********************
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).
Click to expand...

THXS joereeves, I did read your post that you pasted here previously and just not sure still. So I did some more tests today after everyone's suggestions. Here is what I found.

1) Voltage regulator is band new (like less than 2 weeks old) and if I test the grey wire coming off of it, it reads a few volts (cant remember exactly how many as I tested this last week but I think around 4 volts)

2) I tested with my multi-meter today on the plug that plugs into the back of the tach black and grey pins with engine off in on position but not running 0 volts and when it is running i get 0.01 volts.

3) Purple and black wire I get 14 volts

4) If I check ohms on the plug that plugs into the back of the tach using the back and grey pins on the plug I get 00.8 at 200 dial on ohms check

Anyone know what my problem is with a brand new voltage reg that had a non working tach before and after changing it and with the above multi-meter readings? Thxs again for all the input!!!!!!!!! :)
 
joereeves said:
********************
(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging
Click to expand...

THXS joereeves, I did read your post that you pasted here previously and just not sure still. So I did some more tests today after everyone's suggestions. Here is what I found.

1) Voltage regulator is band new (like less than 2 weeks old) and if I test the grey wire coming off of it, it reads a few volts (cant remember exactly how many as I tested this last week but I think around 4 volts)

2) I tested with my multi-meter today on the plug that plugs into the back of the tach black and grey pins with engine off in on position but not running 0 volts and when it is running i get 0.01 volts.

3) Purple and black wire I get 14 volts

4) If I check ohms on the plug that plugs into the back of the tach using the back and grey pins on the plug I get 00.8 at 200 dial on ohms check

Anyone know what my problem is with a brand new voltage reg that had a non working tach before and after changing it and with the above multi-meter readings? Thxs again for all the input!!!!!!!!! :)
 
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