The warning alarm is going off on my '97 150 HP Mercury outboard. I was
ready to change the impeller since water doesn't come out the pee hole
for about 30 seconds after a cold start, and the stream doesn't seem as
strong as usual. What didn't make sense is that the alarm goes off as
soon as the engine is started. It seems to idle around 160 F with ear
muffs on.

I tried switching the garden hose back and forth between the ear muffs
and the fitting next to the pee hole to try to flush any junk out.
After about three repetitions the alarm stopped going off but came back
on after I started the motor a few more times.

Thanks for any help,
Jim