Do not, however, run w/key off because batteries will not charge. Also possible to damage alternator.
My Catalina has a 1983 Yanmar 2GMF diesel engine. When I first purchased my boat about 2 months ago, to start it I would turn the key from 12:00 to about the 1:30 position where it would stay on its own. The alarm would sound and the idiot light on the panel would shine until I hit the start button which would crank the engine. I'd leave the key in that position while the engine was running. To turn off the engine I would pull on the plunger that cuts the fuel. Once the engine stopped running, the alarm would sound and the idiot light would shine. I would turn the key back to 12:00 and the alarm would stop, then I'd remove the key.
Now, however, when I want to start the engine and turn the key to 1:30, no sound is made, the idiot light on the panel does not shine, and when I push the button the engine will not crank. If I turn the key to either the 12:30 or 2:00 position and hold it there, the idiot light shines and the alarm sounds, and I can push the button to start the engine. But the key won't stay at 12:30 or 2:00 on its own. It wants to "rest" at 12:00 or 1:30, so I move it to the 1:30 position and leave it there. When I pull out the plunger to cut the fuel, the engine stops, but the idiot light does not shine and the alarm does not sound.
I'm worried that the way it's behaving now, when the key is at the 1:30 position it's not allowing the batteries to charge (and possibly damaging the alternator).
Any recommendations for troubleshooting / fixing?