Overheating horn

[Domingus]

I recently purchased a 1986 16.5' Traveler (Johnson 28hp). There is no temperature sensor warning alarm of anykind. Do they not mess with such things for a low-end boat, or was there originally some kind of warning system if the cooling system malfunctioned? I certainly want to be notified if the engine starts overheating. How would one go about installing some kind of warning system on this model?

Thanks in advance,
Grant