Engine will not stop.

[mdeitz]

I have a 1995 Mirage by SugarSands with a Merc 120 Sport Jet.<br /><br />Last time out, upon returning to the dock, the engine would not shut off. I turned the key off, pulled the kill lanyard, turned off the batteries, pulled the main fuse on the engine - all without success. Pulled the black wire on the rev limiter and that killed the engine. I have since replaced the rev limiter, but the problem is still there.<br /><br />Any advice/suggestions?<br /><br />Thank you in advance.<br /><br />Mark

 

[Blk-n-Blu]

Re: Engine will not stop.

Have a look at this service bulletin:<br /> http://www.marinemechanic.com/site/page154.html

 

[mdeitz]

Re: Engine will not stop.

Thank you for your quick response!<br /><br />The engine was not "dieseling", it was running "normal". No spitting or coughing. Advancing the throttle resulted in normal acceleration and returning to neutral resulted in smooth idle.<br /><br />I am suspecting the ignition switch - but what do I know? LOL.<br /><br />Thank you!!

 

[Blk-n-Blu]

Re: Engine will not stop.

Yes, could be key switch or a start relay hung up maybe this will help. Something is allowing voltage to the coil when the key is off.

 

[mdeitz]

Re: Engine will not stop.

Update:<br /><br />With all wires from rev limiter attached, engine will not start.<br /><br />With black wire removed, engine starts but will not stop.<br /><br />The only way I have found to stop the engine is to replace the black wire from the rev limiter.<br /><br />??HELP!??

 

[Elk Chaser]

Re: Engine will not stop.

Start from the simple stuff first and work your way from there.<br /><br />Do not start the engine........<br />Turn the key on and then check for 12 V at the + side of the coil, turn the key the off and the 12 V should not be there. If it is then check the key switch the same way.

 

[bahamasboy]

Re: Engine will not stop.

I encountered the same problem yesterday. The I even clipped the wires to the kill lanyard and the key switch. The only way I got it to stop was to pull the center wire on the distributor cap. Here's my question as I'm not a engine buff, is the center wire on the distributor the one that goes to the coil? I can then check the wireing back to the ignition switch. Also, when my battery is connected, I get panel lights and never did before. When I get the panel lights to go off, this should indicate that I've found the short right??<br />Thanks<br />BB

 

[Don S]

Re: Engine will not stop.

Just an FYI, the 120 Sport Jet is a 2 stroke outboard powerhead attached to the jet drive.<br /><br />You're going to need the wiring diagram for that engine to trace the system out.

 

[mdeitz]

Re: Engine will not stop.

Yes, the center wire on the distributor is normally the coil. Removal of this wire terminates the spark to the plugs.<br /><br />It turns out that my problem was an intermittent failure in the key switch, most likely in the ground terminal. I suspected the key switch initially; however, too many people felt marine key switches are pretty much military spec. and therefore, would probably not fail, so I discounted it as the source. After checking the switch in all positions with a meter and finding no problems, I checked every ground on the boat - from the wiring diagram. All tested out fine. I even ran a temporary ground wire straight from the battery. At a loss for any other explanation, I replaced the key switch and everything works fine now. Studying the wiring diagram led me to belive both the key switch and the kill switch function by shorting the coil to ground.<br /><br />Hope this sheds a little light for someone.<br /><br />Thanks to everyone for their comments and advice!<br /><br />Happy boating!!