electrical problems

[Frank mellin]

i have a westerley centaur that is fitted with a nanni 3cyl diesel engine.
the boat wiring had been messed about with when i bought the boat last year but after a lot of work everything was working ok.
A problem has now developed with the engine stop button which sometimes stops the engine ok but other times pressing
it has no effect at all.
If i bridge the terminals on the switch when not working that has no effect apart from creating a spark.it does not stop the engine.
any helpful advice would be appreciated.
FRANK

 

[PeterWright]

Hi Frank,

"Push button to stop" systems on diesel engines work by a solenoid on the injection pump pulling the stop lever which, on simoler systems, would be pulled by a mechanical cable from a "pull to stop" control in the cockpit. There are 2 types - energise go stop and energise to run, the first of these being far more common as loss of 12V supply does not stop the engine and the solenoid gets an easier life, not being energised for long periods.

From your symptoms, you have an intermittent fault with the solenoid circuit or the solenoid itself. You can confirm this by checking that the engine stops reliably when you operate the lever on the injection pump by hand - your operator's manual should tell you where to find it if you don't know.

First suspect is connections in the circuit: those on the button, those on the solenoid and there will be at least one multipin connector in the loom between the control panel and the engine - spade connectors do not serve well in a marine environment. Unplug each connector, clean it, apply contact lube of your choice (vaseline works well) and reconnect.

If that doesn't solve it, perhaps the solenoid is sticking or poorly adjusted. Get a beautiful assistant to push the button while you watch the solenoid. If it moves, but not far enough to stop the engine it's a matter of adjustment between the solenoid and the injection pump, probably by moving the solenoid on its mounting. If the solenoid looks mucky, it could be dirt causing the armature to stick before it's moved enough to stop the engine. If all this fails to cure, the solenoid itself may have a winding fault and need replacing.

Hope that helps,

Peter.

 

[matthewriches]

Where is the boat? If local, can arrange a visit if you like as we have spares that may fit on the van.

These engines are fitted (unless someone’s had a go with it in the past) with a stop solenoid so energise solenoid to STOP engine.

If it is working sometimes and not others but you get a spark when crossing the terminals then I’d do as a Peter says... clean it up, check it’s movement and maybe take it off the engine to test it, ensure you have good voltage at the terminals. If it doesn’t function off the engine on a good battery then find a replacement.

Could be a number of things but usually it’s the fact they are gummed up and stiff so cannot pull, or they are just outright dead with an internal fault. Saw one recently that had a bent end, 2 seconds to bend it back and it worked perfectly.

 

[Tomahawk]

Had similar problems with my Yanmar.. As said above.. probably a sticky solenoid.. Good bit of cleaning and lube will probably help...

In fact do it anyway as it probably could do with a good clean.

 

[westhinder]

Had similar problems with my Yanmar.. As said above.. probably a sticky solenoid.. Good bit of cleaning and lube will probably help...

In fact do it anyway as it probably could do with a good clean.

I had the same when the boat was new to me. As stopping the engine by hand involved dismantling the companionway steps, I added a piece of string to the solenoid so that I could quickly pull-stop the engine if necessary. I haven't needed it since, of course.