Yanmar diesel motor randomly started on its own

[Old Swampy]

In the vein of self starting engines, I once saw an old Rolls Royce (or similar quality car) start when the ignition was turned on (before the starter was activated). Gas engine of course.

[a64pilot]

Had turbine aircraft attempt to start while we were standing beside of it. What was really strange is all aircraft have a "master" switch and it was off, which meant there should have been no power with that switch off. What caused it was the clock power wire was right beside the starter relay wire in a cannon plug and of course they shorted, we removed the clock power wire from the cannon plug for future builds.

[Captain Bill]

The model of Yanmar wasn't mentioned by the op. I have a 3jh3 which developed a leak in the heat exchanger housing which of course was on the far side of the engine and not easily observed. It dripped salt water over my starter and solenoid during a 24 hour run off shore with no wind. The water of course evaporated and the salt eventually bridged the space between the battery connection and the start relay terminal. I never heard the starter over the normal boat noise but I assume it was engaged for a rather long period of time since the rubber cup over the + connection was melted along with the insulation completely burned off of another wire. It took a new heat exchanger, wire, and starter to fix the problem.

Do you guys really turn off the battery switch every time you stop? I just leave my fuel cut offs in the stop position when I'm not using the engines.

[colemj]

Originally Posted by Captain Bill

Do you guys really turn off the battery switch every time you stop? I just leave my fuel cut offs in the stop position when I'm not using the engines.

We do neither, but if our engines were going to start themselves, I would rather the engine actually started than just pumped water until it backfilled the cylinders.

Mark

[belizesailor]

One of my Vovlos did this last season. I inspected the wiring harness and found no issues, but replaced the relays just to be safe. Hasn't happened since, but turing off the battery switches to both engines has now been added to my decomissioning check list.

[tdh1849]

Get the tel # for, " Complete Yacht Service" in Ft/Lauderdale, ask for Mark, the owner ( USMC), they are the local Yanmar/Perkins dealer . Mark knows everything there is to know about Yanmars.

Tell him U got his name from me, initials PN, formerly from there now in Tampa.

[Jim Cate]

All this electrical advice is a waste of time! When you have problems like this, go hire an exorcist...

Jim

[weavis]

I had a car that started itself and rammed in the side of the bridge on 41 in Florida.

The judge didnt buy it either.

sigh.

[Greatketch33]

My boat has a mechanical switch the disconnects the starter battery from the starter.

Bilge pumps and other items are on different batteries.

I tend to use the switch when I leave the boat over time; perhaps throwing the switch whilst swimming or other situations should be part of my practice.