1994 Yamaha 70tlrd question

I owned a PRO 60 Yamaha. The only time the alarm would go off is when the Oil in the reservoir was low.
Have you tried filling the reservoir to the top ?

heres my guess..the pee hole (telltale) is cold water you say,but it should pump hot water when the thermostat opens to cool the water jacket.when the thermostat is closed there is a bypass for the telltale pumping lake water past the waterjacket. the tell tale is only there to see the impeller is correctly working.i’d check the thermostat first. mabey use a inferred thermometer on the water jacket to see the real temp. guages arent trustworthy

Of all the things I've ever done,
I aint never had Too much fun.

Some motors have different alarms for different issues, so if that motor does have multiple alarms that could help further diagnose whether it’s an overheating alarm (probably a steady sound) or an oil alarm (probably beeping).

Since you explained that you addressed the oil stuff and the gauges show correctly, I agree with the others and suspect that it’s a water issue especially since you mention the alarm goes away when you rev it up. When it runs at an idle, is the tell-tale hole peeing out a steady stream?

I had an issue with a newer Mercury this year that the overheating alarm came on and it would not pee out water at an idle, after replacing the impeller for regular maintenance. Turns out that the coupler to connect the lower unit water tube to the upper unit water tube was also replaced, but it wasn’t noticed that the new coupler was much shorter than the old coupler so the water tubes were not really connected. So, pay attention to that when you remove the lower unit and replace the impeller.

Abit, that shouldnt be the problem at low/slow speed.Is it fixed? what fixed it?

Of all the things I've ever done,
I aint never had Too much fun.