Yanmar electrical problem.

[DStegs49]

I have a Legend 37 and from the day I bought it, I've had an intermittent problem with the starter. Of course the surveyor never mentioned it but he is a different story and the broker was no help either. The starter functions intermittently and I've got my problem narrowed to either the starter button or the wiring to it. I replaced the button once. I also have run new wire from the button to the solenoid and replaced the solenoid also. Do I have to increase the wire size? It still has the same problem, push the button and nothing. If I rapidly push the button it usually starts after about 5 or 6 pushes. Once the starter connects, the engine starts immediately. I have heard this is a typical Yanmar problem and I tried the cures I've found but it's still a problem. Anyone else in the same boat, so to speak? Any cures or fixes you have come up with. The starter works immediately if I cross the terminals with a screwdriver but that takes me away from the helm.

 

[dlochner]

Do I have to increase the wire size?

Yes. this is known issue with some Yanmar's. The voltage drop over the wire does not provide enough power to activate the solenoid. For some reason, repeatedly pushing the start button sometimes works, but it is unreliable. I used 10g wire when I replaced mine.

The other related issue is the wiring, the circuit goes from the starter to the switch and back to the solenoid. That wire from the starter to the panel carries all the current for the gauges/idiot lights and anything powered through the key switch. I rewired it so power for the panel and solenoid comes directly from the DC+ bus bar. (fused of course). Haven't had a problem since.

 

[kloudie1]

Pretty much the same here.. I used 10 ga wire from the starter "hot" terminal to bypass all of the sketchy multi-pronged connectors .. I had tried cleaning the connections and that would work for 6-8 months.. If you look at the wiring diagram, you can see that the original power to the panel and back to the solenoid has to get through 4 connections that used to be sometimes clean and waterproof..

 

[ggrizzard]

Wiring Diagram for 3GM29F Yanmar:

 

[duck21]

Here's a previous thread from this form that also details this out with some photos:

Fix for Hunter Starter Wiring Harness issue

I found a number of posts on the forums for a wiring issue that Hunter had with the starter wiring, where the switch or the wires would prevent the starter solenoid from starting the Yanmar (or other engines?). This was apparently due to small wires in the harness or bad contacts in the...

forums.sailboatowners.com

I followed a this schematic/procedure for my dads Yanmar on his Hunter 340, it's been working great.