I have a 1989 Johnson GT 150, and I have noticed a couple of times my warning horn going off. I usually run about 10 minutes or less to a dam and fish with no issue. When I come back drop my friend off to get the truck I idle out to the middle of the river, and that is when it happens. It is a pulsing horn which the manual says is the no oil horn. It has never happened while running, or on the initial trip, only when I return and idle a couple minutes. I have always shut it off right away, and by the time the trailer is ready I start up and no problem. Sorry for the long post...any ideas?