1988 prov 150 temp light continues to stay on

[fishnwv1]

Installed new water pump assembly seems to be pissing fine but temp light came on after idling a few minutes. Checked compression on all cylinders all within a few psi but noticed one plug looked extra clean. Pulled head and had a small leak replaced the gasket still the temp light comes on right as soon as I start the motor. Pulled the other head and replaced gasket and still temp light come on as soon as I start the motor already checked thermostat's on both sides and thermosensors checked out fine. Any advise or help would be great lost on where to go from here.

[boscoe99]

Installed new water pump assembly seems to be pissing fine but temp light came on after idling a few minutes. Checked compression on all cylinders all within a few psi but noticed one plug looked extra clean. Pulled head and had a small leak replaced the gasket still the temp light comes on right as soon as I start the motor. Pulled the other head and replaced gasket and still temp light come on as soon as I start the motor already checked thermostat's on both sides and thermosensors checked out fine. Any advise or help would be great lost on where to go from here.

What kind of light are you talking about? Is it part of a Yamaha tachometer?

Does the light illuminate with just the key being in the "on" position or does it illuminate when the motor is started? Or, does the motor have to run for a bit of time before you see the light?

You did not mention the warning horn. Normally if the light is illuminated due to over temperature the horn will sound. Does your horn work?

[99yam40]

Does the motor have to be running or just turning on the key gets the alarm?
looks like Boscoe be me to it, and asked better questions

[fishnwv1]

It is the temp light on the the tachometer when the ignition switch is turned to the on position the light illuminates and continues to stay on the motor does not have to be started and the alarm buzzer does work as I have trimmed the motor up in the on position out of the water and it sounds as soon as the lower unit is not submerged in water

[99yam40]

another thing that is not doing what it should.

I have never heard of a motor alarming just because it was tilted up out of the water.

Wiring problem is my thoughts/guess

[fishnwv1]

Looks like it may be oil feed pump maybe not pumping any oil even when engaging the emergency oil switch or the control unit kit maybe went out does that sound posssible

[99yam40]

that should not bring in the overheat light or bring in the buzzer all by itself

[bajakeith]

Temp light

Disconnect the temp sensor and see what happens...up near the top of the head...

[fishnwv1]

Oil pump is shorted out anyone know if you can purchase this Asmo Oil Transfer Pump 815100-0020 other than yamaha 190 bucks is a little high for this small motor and pump

[99yam40]

I do not see how a shorted oil pump would bring in a over temp light or cause a buzzer when you tilt the motor up

[fishnwv1]

Problem fixed installed new oil transfer motor yesterday and light goes out after pump fills tank on side of the block and turned key to off position and back on. Far as the alarm buzzer going off when the motor was trimmed up must have been because the oil level in storage tank on the motor would trigger the alarm due to it not being completely full of oil although it was still level with the lower indicator line when motor was level. Thanks for the ideas and responses on this issue.

[99yam40]

It is the temp light on the the tachometer when the ignition switch is turned to the on position the light illuminates and continues to stay on the motor does not have to be started and the alarm buzzer does work as I have trimmed the motor up in the on position out of the water and it sounds as soon as the lower unit is not submerged in water

I still have no idea how the oil level monitoring system could set off the over temp light or alarm