Boat won't shut off

Ok, last night I go to shut off my boat and it wouldn't shut down. Does anyone have any idea what it could be? I just hooked up a new alternator, but I talked to the place I got it and they said it is hooked up right, not that I can figure out what that would have to do with it. Any ideas would be appreciated. Thanks.

does it have a carb. on it? if so the idle might be set too high and all it takes is a turn of a screw to fix it(although i have no idea which one it is)

What year boat? Is it carbourated?

Whoa ... that was wierd ...

Greg ... I think were on the same page!

I had the same problem with my old boat around 6 years ago. If you call the alternator shop and ask them if they have the capacitor that goes inline? I guess its this little capacitor that only allows the electricity to go in one direction. You can shut off your igntion all you want but the boat will not shut down untill you have this capacitor. To shut the boat off for now you can just pull the coil wire. Hope this helps.

look at the bright side... better than not starting... hahaha

What Harrold is referring to is a diode. How many wires on the alternator? Has it ever run on even for a second before the new alternator?

No, it is not carbureted. It's a '95 MCPS205. I'm not too sure about the diode so I will look into that. The alternator has 2 wires (originally). I spoke w/ a mechanic and he thinks I just have it wired wrong, even though it's the way the alternator shop told me. On the alternator is a positive, negative, and 2 'AC' points of attachment. What the mechanic told me is that the 2 wires are probably (1) positive and (2) something w/ the ignition and that I should switch the second wire from the negative to one of the AC connections (seeing as it is grounded since it's attached to the engine block). Peter - no, it had never run on before, which told me right off that it's probably something w/ the alternator. As for just shutting it off by pulling the coil wire, I prefer not to. That shocked the hell out of me.

Thanks for the help.

I'll bet grabbing that coil wire about knocked you to Arizona!

Has it run out of gas yet?

Seriously, how can the alternator cause this? Your boat has a solid state ignition system through the ECM. Am improperly installed alternator should do nothing or start fluctuations, but not confuse the computer into thinking the key is still on, right?

Just about to Arizona. I sat there staring at it wondering how bad it was going to hurt. Well, I guess I found out.

Matt - I have not idea. I don't completely understand the whole ignition system thing so I will just listen to the mechanic I spoke to. But the second wire to my alternator is not a ground, which I should have known. It has something to do w/ the ignition system.

Yes your alternator can cause this by backfeeding power through the system, most likely the alternator is faulty or you may need a diode in the system or your ignition switch is bad, try disconnecting the plug in wires to the alternator and see if it shuts off (with ignition switch turned off too) see if it turns off. if it does bad alt or needs diode if not check ignition switch. good luck and the coil jolt is only about 30-60000 volts hehe

Next time you grab that coil wire you might want to have one of these thingies.

Craig, that would have been nice. I did get smarter the second time and tied a string around the wire.

I got it to shut off now. It needed a ground wire. My old one didn't need it but this one does. But now I have another issue. Everything was going great for a while, but throughout the day, my voltage reading kept dropping. At the beginning, it read 13V and by the end of the day it read 10V.

Also, there is a purple wire that I ended up not hooking up because I have no idea what it would go to. Any ideas? When I touch it to anything, the voltage reading goes to 0, even though it's still running. I sure hope I'm not ruining everything now.