Engine STOP button won't stop diesel engine

[Ocean Cowbuoy]

I have a 6-354....not as modern as your main but had same issue. Was a worn out solenoid. I also did the mcgyver thingy mentioned above to physically have a way to shut off fuel in case solenoid or switch quits and have urgent need to shut down engine. I have had atomic 4's and yanmars in my boats over the past 30 years and now a perkins.....all good engines but I have to say this perkins is a solid beast that never complains.

[KadeyKrogen38]

In a British Motors, Triumpth repair shop they had a sign posted. "Why do the British like warm bear? -- because they have Lucas Refrigerators." You mentioned Lucas solinoids and this came to mind.

[wrwakefield]

Originally Posted by SailingDownhill

I have a Perkins M50 engine that periodically refuses to stop when the STOP button is pushed on the cockpit panel. The engine tried to stop - hesitating over and over. I suspect the fuel shutoff is not completing. Could it be the switch or the relay (and which of the 3 on the engine)? Any ideas?

Welcome to the forum, Downhill.

I don't have a Perkins, but do have an electric stop solenoid.

Once when the engine wouldn't obey the stop command, I discovered the straight threaded linkage connecting the solenoid plunger to the engine stop arm had been self-adjusting its length while it vibrated with the engine running [the linkage length adjustment lock nut was loose...]

Once I readjusted the linkage length [shortened it...] and set the stop nut, all was well.

It sure was puzzling at first, however, as none of that was apparent at first glance...

Here's hoping it is nothing too serious in your case as well...

Cheers! Bill

[Ocean Cowbuoy]

Bill just reminded me that same thing happened after I had installed the new solenoid. It self adjusted itself so that hitting the stop button would only engage the plunger enough to slightly starve the engine. Fixed it quickly. So, based on your original symptoms this may be the issue.

[sy_gilana]

All of the above plus...
The solenoid might have moved in it's mounts, making the core or slug bind up in its tube. Have someone else activate the stop while you watch it, and maybe help it along, that will tell you if its binding.

There are two coils in a stop solenoid, a pull in and a hold in. About 4 Ohms on pull, then about 90 on hold. There is a switch inside, and contacts that open as the slug hits full depth.

[Cheechako]

KISS...

[SailingDownhill]

I could't read the manual pix from Northbound44. Please email to reg_brooks@earthlink.net. Still working my way down from cockpit. Trying to trace wiring harness leads. I removed the start relay and the input contacts are continuous without any connecttions. Should the black/blue (purple/blue?) wire switched by the STOP button at the panel be continuous to the top of the fuel injector pump?

[Ocean Cowbuoy]

What Cheechako said......

[CaptTom]

Originally Posted by wrwakefield

Once I readjusted the linkage length [shortened it...] and set the stop nut, all was well.

I DO have Perkins engines, and I had this happen once, too.

It's easy to check. See if the solenoid pulls the lever all the way to the stops, and if not, adjust. Or just tighten it a little and see if that helps.

[SailingDownhill]

Many Thanks to all. After pulling wires off switches and relays to test (and cleaning and spraying with the RadioShack stuff) I accidentally found out how to hotwire the engine. The STOP button now works. This Beneteau has an fuel shutoff pull at the wheel so that's always available. I suspect the culprit was the Lucas relay since the fuel supply was off & on while the STOP button was depressed. I had this boat 16 years averaging 10nm/gal and plenty of power to get through waves. Very little trouble over the years.

[foufou]

Half of all electrical problems are loose connections

[solmaniac]

I had the same problem. No stop button...but just an ignition key shut off. Took the solenoid off and cleaned it..which resolved for a couple of stops. Then I installed a pull stop cable to the injector pump. Problem solved.

[nigelmercier]

Originally Posted by DeepFrz

Check the wire going to the solenoid and the ground...

And on some engines (MD22) this is via a relay.

[zeehag]

i have a mechanical as opposed to electrical cut off.
i like it this way.
when it fails it is due to other issues, namely runaway diesel.
when engine fails to start--99 percent of time it is air, that one percent is cut off system not adjusted correctly.
if you have a choice, go mechanical over electrical.