Over temp Light Stuck on

[cheap charlie]

Out in the boat on Saturday a over temp light appeared on the rev-counter which has a general warning light amongst 2 others. The boat is a forward steer and obviously has a remote for the outboard. There was no audible alarm just the light on the rev counter. I shut the motor down and removed the engine cover to gauge just how hot the motor was. The motor did'nt seem that hot to me but i thought I would give it 5 minutes with the engine cover of before firing it up again. On firing it up again the light was still displaying and the motor was cool enough to hold my hand on the cylinder head. The teltale had reasonable flow. ( I am replacing the impeller any way as I dont know exactly when it was last replaced) By the time I got home to flush the motor out the engine was stone cold and the over temp light is still displaying. I tried isolating the battery to eliminate the potential of the warning light staying on until it was cleared.

I appears the gauge is a generic non OEM unit and possibly rely s on it's own independent temp sensor but does appear to be part of the original fitout as It matches with the trim and speed gauges.

Can any one confirm if the remote would have an inbuilt alarm for over temp low VRO oil level etc? i recall reading about similar units having a limp home mode inbuilt to limit engine rpm in such a situation?

98 OMC era Johnson 70HP VRO

Edited July 15, 2012 by Cheap Charlie

[Testlab]

Depending on the brand and age of the motor water flow from the telltale indicates the water pump is working but may not tell you if the water is getting around the cooling system correctly. From all you describe it sounds like a crook sensor but I'd not jump to a hasty conclusion.

Find the sensor and disconnect it when the engine is stone cold. If the light goes out then it's likely a crook sensor. There may be more than one sensor (one for the gauge and one for the light).

You can probably buy a service manual for your engine online or borrow one from the local library. I found several after market OMC manuals (Sealoc) at the Hornsby library.