Yanmar 1GM10 start button stopped working

[Renoir]

Greeting All,

I have a little 1986ish Yanmar 1GM10 1 cylinder inboard put-put diesel that performs nicely but recently the start button stopped responding.
It was working during the day where I had to switch the motor on several times but returning to the marina it wouldn't respond at all.
I have noticed in the last couple of weeks that I had to "re-press" the button as the first attempt to failed more frequently.
I understand that from a maintenance point of view that was a good time to start addressing the issue so no need to mention this in your kind reply.
There is no clicking I can hear and the batteries (2) are well charged.
My question is simply this...
What would be the best sequence of fault finding and what could be the most likely issue(s) here?
I'm on a swing buoy so somewhat limited in stepping on and off the boat easily for parts etc...
I have limited experience in electrical works.
Your advice would be greatly appreciated!

Cheers,

Renoir

 

[VicS]

I assume from the age it has the A type panel with a key switch ?

I assume you have checked all connections.

I'd guess from the symptoms you describe that the start button is defective.
I assume the charge and oil warning lights come on as normal and stay illuminated during attempts to start ?

Switch on and short the connections on the button together with a short piece of insulated wire.
If the starter operates it pretty much proves the button to be the trouble.

If it does not then try a direct connection from the ( large) battery positive connection on the starter solenoid to the small white (?)wire on the solenoid . Take care because the engine should crank and start.
If it does not then the starter or solenoid is suspect.

If it cranks when power is applied to the stater solenoid but not when the button is shorted suspect a bad connection in the wiring between the two.

I think that will do for this time of the morning ... report what you find out at a more civilized time of day

 

[ctva]

Good response from the night shift!

First, I’d have a look at using contact cleaner on the wiring connectors between the battery, switch and starter including (if it is like the 2/3GM’s) the hidden connector behind the engine.

 

[PaulRainbow]

I assume from the age it has the A type panel with a key switch ?

I assume you have checked all connections.

I'd guess from the symptoms you describe that the start button is defective.
I assume the charge and oil warning lights come on as normal and stay illuminated during attempts to start ?

Switch on and short the connections on the button together with a short piece of insulated wire.
If the starter operates it pretty much proves the button to be the trouble.

If it does not then try a direct connection from the ( large) battery positive connection on the starter solenoid to the small white (?)wire on the solenoid . Take care because the engine should crank and start.
If it does not then the starter or solenoid is suspect.

If it cranks when power is applied to the stater solenoid but not when the button is shorted suspect a bad connection in the wiring between the two.

I think that will do for this time of the morning ... report what you find out at a more civilized time of day

Exactly what i'd have posted, but not at 02:50

 

[Tranona]

Investigate the connector in the wiring loom. It may need cleaning. There is also a hidden fuse in the loom that can get dirty.

This is a common problem with 1GMs and is almost always bad connections, either as described by Vic or in the loom or back of the panel rather than the switch itself.

 

[blackbeard]

Investigate the connector in the wiring loom. It may need cleaning. There is also a hidden fuse in the loom that can get dirty.

This is a common problem with 1GMs and is almost always bad connections, either as described by Vic or in the loom or back of the panel rather than the switch itself.

Yes. There are several threads on this issue. If, after you have cleaned up all the connections, and the starter motor and solenoid seem OK, and you have checked the starter push switch and it's either OK or has been replaced, the problem persists and the whole issue is driving you to despair, the usual remedy is to fit a relay (Yanmar agents may be able to advise on this but it's not hard) which avoid the volts loss in the loom.

 

[Spyro]

It's a very common problem on Yanmar gm series engines. I suffered from it and cleaning all connectors between the push switch and the starter has fixed it so far. There are several connections that need to be cleaned including the connection at the switch and the solenoid. There is usually at least 2 large with wiring loom plugs one at the back of the engine panel and one near the engine. If that doesn't work consider replacing the wire from the switch to the solenoid.
Some info here http://www.gotosca.org/resources/make-your-tartan-yours/yanmarintermittentstarting

 

[Topcat47]

The first "go to" is the body useless fuse holder in the loom. I've had few problems since replacing it. I bypassed the relevant wire on Snark fitting a sensible fuse holder. The fuse is 30 amp but the "as fitted" connector isn't up to the job. My first "Fix" involved cleaning the contacts and sealing the whole link with shrink wrap. Ok in the short run but replacement was the thing that fixed it for good. My engine is over 10 years old and the button is as good as new. The key switch works as well.