over heat alarm real or not

[viking1978]

I have a 1985 115 hp Evinrude. New to me, no history. I am getting a constant overheat alarm after 1 minute of operation when in the water. I have disconected the tan wire on the heads and still get the alarm when running. How can I determine if the alarm is faulty or a real issue?

VRO oil injection is disabled and I am using 50/1 premix.
The water pump seems to be functioning fine in the water and with ear muffs.
Plenty of water shooting out. Not overly hot.

The fuel side of this system has two filters as the tank had sediment problems in the past. One is the simple clear in line type the other is a larger unit. (about the size of a car oil filter).

Your help in tracking this down is appreciated.

 

[ezeke]

Re: over heat alarm real or not

The tan wire is the ground wire for the horn which gets its positive voltage from the ignition switch accessory post via a purple wire.

If the tan wires are disconnected at the cylinder heads and all VRO wires are disconnected and you still have a horn signal, you have a short in the wiring. The overheat temperature switches in the cylinder heads are simply off or on.

 

[viking1978]

Re: over heat alarm real or not

Thanks, Any help on determining that I have all the VRO wire disconected properly.

 

[ezeke]

Re: over heat alarm real or not

Depending on updating, the VRO has two sets of wires, one from the oil tank and one from the pump itself. When you use premix, all associated wiring from the pump is disconnected on the V4.

The wiring from the pump is connected to the main harness by an 3 or 4 wire amphenol. They are usually found tucked behind the relay box for the tilt and trim.

 

[mikesea]

Re: over heat alarm real or not

If you have a remote control shift box with the horn inside.you might have a short in there. I have seen the horn break from its mount and the terminal hit the inside of box causing the alarm.

 

[viking1978]

Re: over heat alarm real or not

Thanks for the thoughts, I do have a remote and will take it apart to look.