Turn ignition key off and motor still runs??

[ozzydude]

83" 2.5L 120hp mercruiser with points. I'm thinking maybe ignition switch but really unsure. Just started doing this and has been fine so far this season. Thanks for any help u can give.

 

[Bt Doctur]

Re: Turn ignition key off and motor still runs??

the switch would be the first place to start, the alt can back-feed thru a bad diode.If you mean it`s dieseling, thats something different

 

[ozzydude]

Re: Turn ignition key off and motor still runs??

Thanks and no i mean the motor stays running like if the key was on. Anything else to look for incase not the switch? Thanks.

 

[ozzydude]

Re: Turn ignition key off and motor still runs??

the switch would be the first place to start, the alt can back-feed thru a bad diode.If you mean it`s dieseling, thats something different

Sorry BT just realized u also said possible bad diode. Is the diode in the alt or external? I also should have mentioned the wires going to the coil stay warm to the touch with motor turned off and only cool off when i disconnect the positive battery cable. Thanks.

 

[Don S]

Re: Turn ignition key off and motor still runs??

IF the ignition switch is good, you could have a bad starter solenoid keeping the starter engaged.
Could also be as simple as having the main battery cable (where it attaches to the starter) making contact to the small outer terminal of the solenoid.
Or, you have a short in the wireing somewhere.
Have you done any repairs or installations of new "STUFF" on the boat since the last time it worked properly?

 

[ozzydude]

Re: Turn ignition key off and motor still runs??

IF the ignition switch is good, you could have a bad starter solenoid keeping the starter engaged.
Could also be as simple as having the main battery cable (where it attaches to the starter) making contact to the small outer terminal of the solenoid.
Or, you have a short in the wireing somewhere.
Have you done any repairs or installations of new "STUFF" on the boat since the last time it worked properly?

Nope havent touched anything on motor or touched any wires since it was working ok. I checked the connections u talked about and all seem good. I did read up on the diode situation and it stated that a bad diode could drain battery overnight, so i checked for a battery draw and i do have one but dont have right tools to see how bad(i just used a test light). So im gonna check it again in the morning. Could a bad ignition switch cause a battery drain? Everything on boat is original since 83" besides interior that i replaced a month ago. Thanks.

 

[Bt Doctur]

Re: Turn ignition key off and motor still runs??

In the "run " position ,yes

 

[diehard]

Re: Turn ignition key off and motor still runs??

when you shut your key off and it keeps running turn somthing on that will give you a power draw trim pump ,blower ,bilge pump,anything if it is a diode that should shut off engine.. on my old boat this happened to me a cut the small wire going to my alternater and spliced a light bulb in the wire ..the bulb would create just enough draw to shut off engine when i turned off key

 

[ozzydude]

Re: Turn ignition key off and motor still runs??

Update:..... I wish i could say what it was but i cant cause i tried it again this morning and it was working fine. The battery draw is also gone. Appreciate the help and we'll just keep an eye on it and see what happends. Thanks!

 

[Don S]

Re: Turn ignition key off and motor still runs??

It's not over or cured.
You have an intermittant problem. It WILL happen again.