Yanmar starting query.

majdrew

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Hi Folks!

I have a 1GM10. Last summer sometimes I had trouble starting it.
I would push the button, but sometimes it took 4 or 5 pushes of the button for the engine to start, just didn't turn over at all. Couldn't hear any noise. Then for no apparent reason it would turn over and start no problem. Sometimes it would start on the first go..

I'm assuming it's some sort of electrical fault.
Besides the connections, is there anything else I could check?
Thanks for any advice!
 
My 3GM did this last season. I too thought "switch" but a quick continuity check proved it fine.

It turned out to be the solenoid piggy-backed on the starter motor that was dry and just needed lubrication.
 
can be a variety of things, check the connector where the gear linkage is, also check inline fuse there is not dirty. if all those are ok then its getting the solenoid and the starter itself checked, i have had this where the armature has two segments burned out opposite each other.

steve
 
Had exactly the same problem with my 2GM and it drove me mad for 3 seasons. After spending £££s to no avail with a marine engineer, stripping the starter motor, checking the solenoid etc etc, and lots of ideas from well meaning posters on this forum, it turned out to be the plug-in connectors in the wiring loom.

On my engine, behind the switch panel is a multi-plug which then plugs into a wiring loom and then another multi-plug before the engine. Took these plugs apart, cleaned up using WD40 put them back together and it all worked fine all season.

So, check the obvious and easy things first before you start doing anything major.
 
That's brilliant, thank you all!

I'll write all these suggestions down and go through them one by one.

Thanks again!
 
This sounds just like a problem I have.
Engine has never failed to start ... eventually, sometimes after half a dozen or so presses on the starter button.
Drove me crazy.
Tried everything I could think of ... every electrical contact I could reach. Took the starter motor to an automotive specialist who found nothing wrong. Yanmar agents said it was, or wasn't, the solenoid.
Every time I approached with a voltmeter the problem cured itself, only to return once I put the voltmeter away.
There was a bit of a clue - when I pressed the starter, the oil pressure/generator warning lights dimmed, so the engine electrics were not seeing 12 volts. I wondered why, and after much cleaning of contacts which had no effect whatever, I began to suspect a connector which carries the 12 volt supply to the panel. This is connected during installation and cannot be disconnected.

I disconnected it and cleaned up the contacts, re-connected, the engine then started as it should ... sometimes. Often enough that I thought I might have cured the problem, the problem then recurs and I can hear the engine laughing at me.

I'm told that the solenoid, if it doesn't get the 12 volts it craves, can develop dirty patches on the contacts which don't conduct as they should, at least not until after several presses on the starter. So it might have been the bad contact in the connector having an effect on the solenoid contacts. (You may think it's a trifle unlucky if fault A causes fault B which gives the symptoms of fault A even when fault A has been rectified ...) As the system now seems much improved and works most of the time, and as I've said, the engine always starts eventually, I haven't pursued this to the extent of buying a new solenoid just to find out if it makes any difference.

Careful cleaning of every contact in sight, logging the occasions when the fault occurs, investment in 2 voltmeters (one digital for accuracy, one cheap moving coil for fast response), and the growth of a sense of humour, can all help. I am beginning to think that the problem is more likely to lie with an obscure bad contact in some out-of-the-way place than with some expensive spare part that must be replaced.
 
Thanks blackbeard that's a comprehensive reply.

Actually, I feel a whole lot better after reading these suggestions.. I feel that it's something that I can fix, just spend some time careful cleaning, and not spend more money on.. that's good!!!

All the best everyone!
 
Also check the negative return connections - engine block to the neg on the battery. These often get missed when checking.

Another way of testing for poor connections with a DVM: connect the DVM positive lead to the POSITIVE battery terminal (doesnt matter too much which way as the DVM just reads it as a negative voltage). When you connect the other lead to anything further down the positive wiring, it will then give you the voltage difference. More than around a volt or so indicates a probable bad connection. Zero reading indicates no connection of course! Do the same between the negative terminal and the engine block or negative to check negative return circuits.

Try the starter circuits again on load with the starter motor operating. The heavy current may show up a connector that is OK off load, but not passing the full amperage.
 
Blackbeard's description of oil light dimming is exactly the same as mine. I was babboozled by the apparent presence of 12v everywhere yet no action. What had happened was that the solenoid shuttle was a bit sticky, the coil took the current required, but stayed put. Ergo a small voltage drop owing to the solenoid actuator current, and no connection made to fire the starter. This could be exacerbated by voltage drop due to poor contacts in switchery or terminals.

It is, imho, unlikely that dirty earths etc are involved because this woud give extinction of oil lights on pressing the button, and probably weak cranking when it did go. No action, a bit of dimming and healthy starts when contact is made almost certainly = solenoid.

It is easy enough to apply 12v direct from the battery via a piece of wire to the solenoid input terminal, that'll tell you straight away if the thing is sticky or not. If in doubt, hoik it out, dismantle and lube the solenoid (it probably needs doing every few years anyway) and refit. It is dead easy to check it's operation on the bench (ot the pilot berth in my case)

Yanmar workshop and repair manuals (which are excellent) are available FOC on the net.
 
Thanks MASH!

I'll bring home the solenoid I think after reading this, and clean and lubricate.. sounds like it can't do any harm to do this, and could well solve the problem! I don't have a manual, but I can take what I can apart and grease I guess should be no problem..

Thanks for all your help guys!
 
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