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Tacho-problems Evinrude 115 -1979

M

Mr Mohl

New member
Tacho is dead!
When turning key the taco normally goes down from 1 to 0 but nothing happens, even when starting the engine nothing is happening. Tried to change from the Quicksilver tacho to the old original Evinrude tacho but no difference. Checking the outlet from the throttle reglage with a ohm-meter the black and purple seems to be in contact. Tied o put black from the an other earth point direct to the tacho but no difference. Now the engine is dead, no choke, o starter but the tilt and trim works.

Where to find the solution to this fault?
Where to find he fuses n the engine?

Kind regard and thanks in advance /Thomas /Sweden/
 
you probably blew a 20 amp inline fuse...its under the cowl in a red wire near the starter solenoid...

on the tach not working...what does the voltmeter read at 2k rpm?
 
After you change the fuse, check the rectifier. That's the usual cause of a tach not working, and if its bad it also means your battery isn't charging.
 
PROBLEM NOTSOLVED! L
Rectifier (new) changed, fuse changed but tacho needlenot mowing.
I have 12v to the tacho (black and purple).
I have checked cables from tacho to the engine andhave no broken cables.
On my other engine, Evinrude 90 hp from 1991, there isa short sound (pip) when turning the key one step and at the same time theneedle drop from 1 to 0. On the 115 nothing happens! No sound (pip) and no movement.I have also taken the tacho from the 90 and install that to the 115 but nochange. The engine starts well and runs great.
Any idea?
Kind regards! /thomas

 
As I don´t have any tacho I can´t run it 2.000 RPM, theboat has no voltmeter as well. I will borrow a mobile tacho and install avoltmeter and let you know.
Many thanks for your swift reply! /Thomas

 
Summary:
Tachometer functions perfectly on the 90hp engine.
Tachometer does not function on the 115hp engine.

You install the 90hp tachometer on the 115hp engine... the tachometer does not function!

Conclusion, pertaining to the 115hp engine:
1 - Either 12v is not present at the purple wire leading to the tachometer... OR
2 - The black wire leading from the tachometer is not grounded... OR
3 - Something is wrong with the three wire rectifier assembly.

The first two causes above are easily checked. The rectifier can be tested as follows.

(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************
(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************

It's also possible that the battery charging side of the stator has failed... BUT... if it has, it'll be the first one I've encountered in over 30 years. To test.... disconnect the two yellow wires from the terminal strip. With a ohm meter, you should have continuity between those two wires... BUT... on a high ohm setting, no continuity, no reading should exist between either yellow wire and ground.

Let us know what you find.
 
Last edited:
Many thanks for your swift reply and instructions.Last Friday I purchased I new original OMC rectifier and fitted it to theengine in the same way the old one was and no difference on the tacho. Therectifier have 1 yellow, 1 yellow/grey and 1 red wire.
I have 12v on the purple and the black is grounded……………….
Kind regards! /Thomas

 
Mr Mohl said:
Many thanks for your swift reply and instructions.Last Friday I purchased I new original OMC rectifier and fitted it to the engine in the same way the old one was and no difference on the tacho. The rectifier have 1 yellow, 1 yellow/grey and 1 red wire.
I have 12v on the purple and the black is grounded………………. Kind regards! /Thomas
Click to expand...

Read over post #10 carefully. If everything there is as it should be, you either have the battery hooked up backwards, hooked up properly but charged backwards, or have a break in the tachometer gray sensor wire.

The black wire leading from the tachometer.... what is it grounded to?
 
OK,
The black is grounded to a bolt at a point at the enginewhere a couple of other ground connections, the fuse (at the red wire) and anotherconnection is fixed. Looks like original mounted.
Kind regards! /Thomas

 
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