Starter still cranks after engine start

[Jyhouse7]

Chaparral 180 Mercruiser 3.0
A few days ago on the water my boat started just fine but I heard some extra racket going on and found that the starter was still cranking while the engine was running. I turned the key to off and removed the key and it was still cranking. I was able to get it to stop after jiggling the key so I assume the ignition switch is junk. I tried again later and it started fine no issues but an attempt an hour later and I had the same issue. Any thoughts? Thanks!!!

 

[stonyloam]

Three possibilities here, ignition switch, slave selonoid sticking, starter selonoid sticking. The problem with intermittent problems, is that they are intermittent. Since it stopped when you wiggled the switch, yeah most likely it is the switch, might just want to go ahead and change it. Use a good marine rated switch. Check over the wiring to make sure it is in good shape, a short between two wires could Aldo do it, though it is not likely.

 

[alldodge]

Agree could be any of the three, and since this is a 3.0 you may have sufficient room to get at the starter. If you do maybe remove the starter check the gear and have bench test it. Might be the switch but could also be some rust building up on the bendix

 

[stonyloam]

Yeah, normally I would not suggest throwing parts at a problem, but replacing a ignition switch is so much easier than pulling the starter or slave it might be worth taking a chance, especially since it is an intermittent problem. Testing could involve a bunch of tries and a lot of cranking before it happen again. Wiggling the switch stopped it (maybe) so I guess I would lean that way.

 

[Jyhouse7]

Thanks for all the help!! I'll start at the switch and move on accordingly! Thanks all!

 

[Silvertip]

I certainly would not start by replacing the ignition switch. Troubleshoot it by bypassing the "S" terminal with any simple momentary push button switch you can find. About $1.50 at Radio Shack or any home store. Disconnect the wire on the "S" terminal and connect it to one terminal on the switch. Connect +12 volts to the other terminal. When you start the engine, DON'T turn the key to START, just turn it to RUN. Now activate the temporary switch. After a few tries you will know if it is or is not the ignition switch.

 

[Volphin]

This happened to me on the water once and it was NOT pretty. The amp draw melted my battery cable and caused a small fire. There is a REASON you keep an extinguisher on board! LOL I had a defective slave solenoid. The solenoid was peanuts compared to the battery! grrrrr

 

[KnottedUp]

Have a 1999 90 Johnson. Changed the ignition switch a few months ago. Had been running fine. Today, I noticed my starter was still running (not engaged) after the motor was running. To verify, while the motor was running, I pushed in the choke to kill the engine. When it had stopped, the starter was still running. Tried the old standard (whacked the starter a few times) with no success. Any suggestions? BTW - Switch was an original OMC replacement switch.