Yanmar 56 4-Cylinder Won't Stop

[plane sailing]

my yanmar wont stop when i push the stop button on the panel.
it stops only when i push the main stop on the engine... any ideas please.
Paul.

[skipmac]

Not sure of your knowledge level of diesels so pardon me if I explain something that is too simple or you already know.

Diesels are shut down by stopping the fuel supply to the engine. If you push a button to do this it is done indirectly by the button operating a solenoid that pushes or pulls on the valve that shuts off the fuel.

If one button or switch works and the other doesn't then the shut off part itself must be working so the problem will be in the button that does not work or the wires going to it. If the panel is in the cockpit and exposed to weather then most likely a corroded connection where the electric wires connect to the button or the contacts inside the button itself are bad.

Fix would be to check the wires on the back of the button to make sure they are clean and connect tightly to the button. If they appear good then could be the button. Do you have a VOM (electric meter/tester)? If so, check the button to see if it closes the circuit when you push it.

[never monday]

when you push the on engine, you are pushing the actuator rod. Mechaniclly functioning the actuator. This is an electrical problem. Verify voltage at the actuator connection. Then probably replace the actuator.

[plane sailing]

thanks for the info skpmac. i will pull the panel off and have a look . the stop button is covered in rubber so behind might be the problem. glad to hear that it could be this simple and inexpensive. i was thinkin the worst. Paul.

[mikefp60]

All of the information above is accurate. Had the same issue. Pulled off the rubber boot and sprayed circuit cleaner around the button while pressing it. Did this a few times and it fixed it. We will see how long the fix lasts. Circuit cleaner is a spray can with a straw tube. Like WD-40 but a cleaner that evaporates quickly.

[Charlie]

One very simple problem witht he button is that if the key is not in the on position on my 56 hp yanmar the electricity to the actuator is cut off and the engine won't shut down. Turn the key on and the engine shuts down.

[plane sailing]

WOW thanks guys, looks like i got plenty of options to look into.
hopefully the least expensive and easiest, its a real pain to go below
and remove engine cover etc. etc. etc. amazed at the quick and accurate
responses on this forum.... long time reader first time poster..
that's about to change. thanx again Paul.

[Gallivanters]

Paul,
I believe I have the same engine as you and mine developed the same problem shortly after I installed it. It was a new engine.

Have someone at the control panel, with the ignition on but engine NOT running. Put your ear by the fuel pump and have your assistant push the stop button a couple of times. If you can hear a "click" sound - then gently slip the rubber boot off the solenoid and clean & lubricate the actuator shaft the solenoid. All I needed was a paper towel and a teflon spray lubricant. Problem was solved in less than five minutes.

The engine had less than 100 hrs when the problem occured and the above technique has solved it for the past 1700 hrs' usage.

Charlie - I've been lead to believe that your alternator diodes will be destroyed immediately if the ignition is switched off while the engine is running... is this not the case with your engine?

To Life!

Kirk

[never monday]

Originally Posted by Gallivanters

Charlie - I've been lead to believe that your alternator diodes will be destroyed immediately if the battery is switched off while the engine is running... is this not the case with your engine?

To Life!

Kirk

I repaired your quote

[Charlie]

Ok NM so if the batteries are switched off then the diodes are fried. On the Yanmar 4JH4E as I have it installed the battery switch is something completely different from the ignition switch. I assume this is typical. I have a battery switch that controls the start battery. I turn the switch off when I am at anchor so that I do not draw down the start battery but never when the engine is running.

[AnsleyS]

Paul,

I have the same engine and I have had the same problem. Have someone push the stop button while you are down by the engine and you will see whether the solenoid activates. If it does make sure that the bolt that connects the solenoid to the fuel valve is screwed all the way in. Mine came loose and although the solenoid was activating the valve was not closing all the way.

Ansley Sawyer
SV Pacem

[plane sailing]

I'm glad its "wont stop" rather than "wont start" I will check all these ideas and let you know, what i find.

[plane sailing]

well.... thanx for all the replies, i found a wire broken in the loom from the control box to the engine... so a bit of solder and shrinkplastic and it now works...lol i thought it was worse so very relieved,