My 92 Yamaha 115hp outboard ran low on oil (not empty) recently,
activating the warning horn, and cutting rpm back to 2000 rpm. I
refilled with oil, and have a pointer triangle above the full oil
indicator. Now it runs strong for about 5 minutes then I hear one beep
from the audible horn followed by the motor cutting back to 2000 rpm.
If I reduce to idle for a minute or so, I can resume at full speed for
another 5 minutes. Oil is full with a triangle pointing at the green
full indication. However, the red empty indicator has a red square
above it, where the triangle pointer would go. I don't remember if the
red square was there before this happened or not.

Does this sound like it is overheating, or is the oil level sensor
malfunctioning? Also, is it normal to have that small red square above
the empty indicator, or is that a holdover from letting it run low.

Thanks,

Lee