Failure of Starter of Yanmar Diesel to Disengage

[Kings Gambit]

After about 1750 hr of diesel run-time, the starter on my 1999 3JH3E remained engaged on the last start up and regrettably, for me, was not caught in time to prevent the starter from "burning up." Does anyone know-- is this something that happens often in Yanmar diesels near that number of hours? What are the known, or possible, causes? What are possible "collateral" damages? The starter unit is a starter-solenoid combination. The ignition switch will also be replaced. What else should be inspected or replaced?

 

[Benny17441]

No its not a problem with Yanmar. Possible causes worn gear teeth on the starter, loose starter, worn bearings, damaged or bent starter shaft, damaged or worn flywheel gear ring. How damage occurs could be by repeated late disengagement of the throwout gear due to operator error or faulty starter button. Inspect the replacement starter to make sure it turns true with no wobble. Inspect the flywheel teeth for any damage. If any teeth are bent or chewed up replace . Hopefully it was a one time event possibly allowed by play in the shaft from worn starter bearings with minimum damage to the flywheel teeth. Good luck.

 

[Ron20324]

Sounds like the same problem as with cars. The Bendix spring does not push the gear away from the flywheel when the key is released from the "start". So. maybe a broken spring?

 

[kloudie1]

The push buttons/switches are famous for getting a little water/corrosion then sticking "on" and frying the starter.. Next item would be a sticky solenoid.. The starter gear is mechanically engaged when the solenoid switches "on". If the solenoid armature sticks, it can keep the starter running and fry the starter motor. Usually the starter and solenoid unit are the only things damaged, but do check the items Benny listed..

 

[Kings Gambit]

Thanks all for the replies. I'll ask the mechanic to inspect those items Benny mentioned with installation of the new starter. I can now understand why cruisers sometimes list a starter/solenoid assembly as a "spare parts" item that they carry. We could easily have been stuck out somewhere on a dying wind, or in some tight spot at anchor where we needed or wished for the diesel to get underway. It's an insidious little problem that's not easy to catch (at least the first time) b/f the starter may be lost. There is a sound that you can barely hear over the diesel--it's a hissing-type sound similar to the sound of water spraying from a hose nozzle and hitting hot metal. At first I thought I had split a hose and went below to look for it. When I opened the engine compartment I was greeted with smoke and the smell of an electrical short. The sound was the "whining" of the starter spinning. Fortunately the engine was operating near or at idle speed (low RPM) for the time it took me to discover the problem. As luck would have it a Harbor Patrol vessel was going past us just at the time I cut the engine and we became adrift in the main fairway of the harbor; fortunately with a light tail wind that kept us in the middle and not one that blew us across into the slips. Of course I was also heading for the anchor locker. I couldn't go below when I first noticed the sound b/c there was no one to take the wheel at that moment as I was backing from the slip, etc. For some reason I was out of my "normal" routine of allowing the diesel to run for 15-20 min, or longer, before departing the slip!!

 

[Chief RA]

KG: Have the old one rebuilt and then you will have a spare. Chief

 

[Kings Gambit]

KG: Have the old one rebuilt and then you will have a spare. Chief

Yeah, that was my plan if I can do the solenoid too; it's a combination set up--starter plus solenoid. I don't know much about rebuilding these things.

 

[Stu Jackson]

KG, sorry to hear about your issues.

Find a local alternator repair shop, they do starters, too, same guts/ideas.

One of the best things I did was find one I know & trust. Always a good investment in your time.

I learned of one close to us by reading many other boating forums and found one on the C36 Forum

Good luck.

 

[mz4wheeler]

There is a sound, however, that you can just hear over the diesel--it's a hissing-type sound similar to the sound of water spraying from a hose nozzle and hitting hot metal.

This happened to me and I recognized that it was a stuck starter. I took a hammer and smacked it and it released. I then had the starter rebuilt. Been fine ever since.

 

[jerry]

I also had this problem. Did not know until tried to shut down engine when under sail. Engine restarted after I pushed the shutoff valve closed. It repeated, then I realized the starter was still engaged. When I shut off the battery connection the starter shut off.
It ended up being the switch to starter selonoid wire was shorted. I strung a new wire from the switch to selonoid and disconnected the old wire. All worked well. Took about 15 minutes to rewire.

 

[Kings Gambit]

It ended up being the switch to starter selonoid wire was shorted. I strung a new wire from the switch to selonoid and disconnected the old wire. All worked well. Took about 15 minutes to rewire.

I'm always vexed by these sudden failures w/o warning of something that seemed to be operating perfectly well a few days or hours earlier. The starter of a diesel engine on a sailboat simply does not get all that much usage. I've never had one fail on my car(s) after literally thousands of starts, for example--so it's a bit bewildering. I'm more inclined to look toward an electrical short in the switch as the primary cause--but where did that come from all of a sudden--water somewhere shorting out the solenoid terminal, or similar? The ignition on the console is very low, just inches (a few centimeters) above the sole of the cockpit where I frequently dump seawater when cleaning the teak there. Of course getting pooped or similar would put a lot more seawater around the console than that, perhaps even half way up the lockers, that might find its way in. Design flaw or poor maintenance of the watertight sealing around the instrument panel? Time for a look!

 

[Kings Gambit]

Replaced the starter yesterday on the 3JH3E with a Yanmar replacement (built by Hitachi). All seems good; no "collateral damage" in evidence. Ready for the next adventure!