Found this on another site but may help ya out. Mine is a Merc but had a float switch in the oil reserve tank get saturated and caused the alarm to sound. Good Luck.
There are a couple of situations dealing with the oil system that will give a continuous alarm. If the oil warning module (small black box below starter on right side of engine with 5 wires coming out of it) is bad it will give a continuous alarm or if the oil level float switch inside the oil tank is stuck or bad it will give a continuous alarm. Also the temp sending unit wire (located on the back of engine by the sparkplugs) goes to the oil warning module. If the temp sending unit is bad or the wire (tan w/lt. blue ) is shorted to ground somewhere it will give a continuous alarm. You can remove the tan/light blue wire coming from temp sending unit to the oil warning module, if the alarm stops it's probably a bad temp sending unit if it continues unplug the light blue wires going to the oil sending switch in the oil tank, if the alarm stops you have found the problem. If after unpluging the temp sending unit and the oil sending switch and the alarm still continues it is probably a bad oil warning module.