'99 Mercury four stroke issue

[JRinNE]

Was out this weekend made a couple of 15 minute runs to different spots with no issues. Got to next spot, was cruising about 5mph with engine trimmed up slightly, watching sonar and the engine alarm sounded. I looked as I went to shut it down and there was a good stream of water coming out motor. I also checked the oil and it was at the correct level. Waited a while fired it up and headed for the ramp with no problems. When I went to load it up, I trimmed the motor up some and idled up to the trailer the alarm sounded again. Any ideas?