30 HP Waring indicator

My 2002 30 HP manual tiller warning indicator was activated yesterday after about 15 miles of running. I am certain that the warning was not temperature related as I had good cool water flow out of motor. My concern is that I had a 1/2 of oil reservoir of oil. This motor is new to me so I'm not that familiar with it. Is it likely that the filter in the oil reservoir is restricted? Is the alarm activated at low oil level, or does it somehow measure flow? Trying to avoid bringing it to the shop again, who just hit me up $380 for caburator cleaning. The motor RPM was limited, so I limped back to the landing. Any pointers on how this oil sytem works would be nice. I don't want to take any more ribbing from my buddies

[boats.net]

The warning can be activated from low oil level in oil tank or by engine overheating, engine can be overheated even though water is cool coming out tell-tale hose. If you had carb trouble then it's probably been sitting up for a long time and the water pump may need to be replaced also.

I shutdown motor and ran at idle for probably 20 minutes with alarm still active. I'm sure it isn't the thermostat because I disconnected it to see if there was a change and I still had same problem. Is the oil alarm only activated if there is a low level? If yes, is there a float switch, or some other means to determine level. I had about a 1/3 of tank of oil. What if there was sufficent oil in tank, but filter clogged? Would this activate the alarm?