120 V4 Overheat warning

L

Lslem

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Have a 1989 Evin V4 which gave me an overheat warning (steady horn) after about 10-15 minutes of running just above idle. Checked both temp sensors using the hot oil method; both appear to operate normally. When I ground the tan wire (from either sensor) with the ign ON, the horn sounds but when I UNground the wire the horn continues to sound. My (Clymer) manual shows a diode in that circuit, but I have no clue where it's located. I'm suspecting either that diode or possibly the horn itself. Unable to find any shorting or chafed wires etc.
Anybody else ever have this problem?
 
Joe Reeves

Joe Reeves

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Re: 120 V4 Overheat warning

With the engine running and the problem (horn sounding) taking place, Remove the TAN wire FROM THE HORN itself. If the horn continues to sound with that TAN wire removed from the horn, replace the horn.
 
L

Lslem

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Re: 120 V4 Overheat warning

Well, I guess that was a good place to start, but, unfortunately, with ignition switch on, grounding either tan wire at the sensor, the horn sounds, and continues to sound (sensor UNgrounded) until I pull the wire off the horn, then it quits.
So, I'm kinda back to square one. I'm thinking I should be able to locate the diode shown in the wiring diagram, but so far, no luck.

Would appreciate further input from anyone who had this or similar problem with this series of Evinrude.

Thnx, Vice Admiral, it was as good a place to start as any.
 
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ezeke

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Re: 120 V4 Overheat warning

The blocking diode is located in the tan wire in the red connector harness, 19-3/4" from the inside edge of the connector.

Before you tear up your harness, though, use your ohmmeter on the tan wire circuit to confirm that the diode is not functioning.
 
L

Lslem

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Re: 120 V4 Overheat warning

Ezeke, I'm a little unclear as to the direction of the dimension you gave me. I'm assuming back toward the rear of the engine, correct?
 
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ezeke

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Re: 120 V4 Overheat warning

Let's call the engine part of the harness system the engine harness. It's in the engine harness.

Tan wires run from each temperature switch and from the powerpack, then into the harness. The diode is after those and before the VRO amphenol tan wires.

There is a diode repair kit available from the dealership. The most important thing to determine is how voltage got to the tan wire to kill the diode in the first place, otherwise you will have to keep fixing it.
 
L

Lslem

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Re: 120 V4 Overheat warning

Ezeke, tnx for your help....turns out there was a wire under the power pack cover which had chafed against the mount bolt and into the conductor...not sure if that wire was in the overheat circuit or not, but after running a full tank of gas thru it at different speeds including a lot of wide open throttle, I never got a peep out of the warning horn.
I'm hoping that was the problem. Time will tell.
Tnx again.
 
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