R21-EC Puzzling Start Problem

[abcandjrc]

We took our R21-EC out yesterday. There were problems getting the starter motor to engage. Here is what I can tell you for certain:

1. The engine has 440 hours. The boat hadn't been used since April 26 but it has sat much longer in the past without activating the starter.
2. The shifter was in neutral and the neutral safety switch was not involved. (See further description below.)
3. The battery was fully charged and the terminals are clean and tight.
4. The panel was active. All buzzers and lights were working. Pushing the stop button engaged the fuel shutoff solenoid just fine.

During the failure mode, with the engine cover lifted, there was a light clicking sound each time I turned the key to start. If I moved the lever to forward or reverse the clicking did not occur. This is one way I know the neutral safety switch was not involved. The clicking was coming from a Hitachi MS5C-321 solenoid atop the engine. I am presuming this is a pre-starter-solenoid-solenoid, installed by Yanmar, which then engages the starter solenoid if it is happy. (????why????) I do not know if the Hitachi solenoid itself is the problem or not, but eventually, after multiple tries, the starter engaged and the engine started normally. It started normally after that except for one time when I was not fully centered on the neutral safety switch and centering the shifter a bit did the trick. After that, just to check what was happening I started and stopped the engine several times, all with no problem.





The connections to the Hitachi solenoid are tight and clean. The only thing I note is that what appear to be two halves will “wiggle” a very small amount with respect to each other. It appears there is a seal between them, and it looks good. The part has never been wet to my knowledge. The light corrosion discoloration is endemic to boats in salt water whether wet or not.

Today I tested the starter solenoid by using The-Key-That-Starts-Any-Diesel (jumping from the starter power lead directly to the solenoid terminal) and the starter engaged each time. I know that is not definitive since the same thing might have happened if I were using the key. But a failure in a Yanmar starter solenoid seems highly unlikely, especially at this young age. But I wonder if the Hitachi solenoid may be the real culprit. I have never really listened to the click on it in the past, so don't know how loud it should be. Maybe it is not slamming it's contact home hard enough and there was some oxidation on them.

I hope to track down the engine wiring diagrams but thought I would put this out while I had the time since I suspect it may take some doing to find them.

Have any of you had a similar experience? If any of you would be so kind as to try to wiggle the two halves of your Hitachi Solenoid to see if they move slightly with respect to each other, I would be grateful.

 

[dalee62]

Just came back from checking the solenoid, mine is solid. No movement at all.

Mine went at 70 hours so you have done well. If you take it off a mechanic he can do something like a continuity test. That's how they determined mine was shot. They told me I could jump across this solenoid as well if I did not want to get down on my hands and knees at the starter. I debated having a new one on board but decided that if I could just jump across it then there was no point in having another one handy. The boat now has just over 750 hours and no problems.

Hope that helps.

Dave

 

[abcandjrc]

Just came back from checking the solenoid, mine is solid. No movement at all.

Mine went at 70 hours so you have done well. If you take it off a mechanic he can do something like a continuity test. That's how they determined mine was shot. They told me I could jump across this solenoid as well if I did not want to get down on my hands and knees at the starter. I debated having a new one on board but decided that if I could just jump across it then there was no point in having another one handy. The boat now has just over 750 hours and no problems.

Hope that helps.

Dave

Thank you very much. That probably answers the question quite well. I think mine is just not pulling-in enough to close its internal points. Maybe because the two halves have come loose from each other. I will get one on order as a spare if nothing else.

I hadn't thought about jumping at the Hitachi solenoid itself. I guess going across the two heavy lugs should feed the starter motor. Good point. That should also remove the starter solenoid itself from the question.