Intermittent Starting Problem

[Rob McClain]

I am attempting to troubleshoot a peculiar starting problem and could use assistance on places to look. I have a Yanmar 3GM30 diesel. When I hit the starter button while at the dock the engine fires quickly each time with no problem. However, after a day of sailing and I am preparing to return to the dock, when I hit the starter button nothing happens the first time. I am finding that I need to hit the button about 3 times before anything occurs and then the engine fires. I have assured that the kill throttle is fully depressed so that is not the problem. The batteries are full, charged, and the terminals are clean and tight. I've also checked other connections and the ground wire is good. I've wondered about the starter button itself, but that would not appear to be the problem since I only encounter the difficulty after being out on the bay (regardless of any amount of heal). I've never encountered this problem while at the dock - only while out on the water. Any thoughts?

Rob

 

[Patrick17430]

I had the same problem. I cleaned and tightened all the connections to the starter button and key switch behind the gauge panel and she fire's every time now .

 

[RichH]

Extremely common problem in both QM and GM Yanmars. The problem is they have non-tinned wiring in their control panels and especially the connectors and inline fuse for the primary solenoid circuit (battery-keyswitch-pushbutton-fuse-starter solenoid) easily develop corrosion. When the corrosion dries out due to engine heat it becomes less conductive than when its at ambient temperature ... so your engine will start when cold but wont when its hot.

The chief bad actor is usually the engine mounted fuse in the solenoid circuit .... replace it with a tinned ancor type fuse holder and fuse. The next worse is the push button ... if the amperage goes up because of a resistance in the circuit the contacts of the push button will arc and leave a carbon deposit on the contacts that is non-conductive when dry. Next is the connectors on the keyswitch and the keyswitch itself. Also a bad engine ground will do this.

Use a digital voltmeter and check the circuit from the keyswitch and each component/connector all the way to the solenoid. Replace all the 'sections' / components that show a voltage drop. Do your checing aft er the the engine has been operating for a while - so that all the corrosion in the connectors, etc. has some time to dry-out.

 

[svenusa]

connectors

I have a 2GM20 and had similar problem.. There were two or three connectors on the back of the engine that were a little furry.. after cleaning the terminals with a little sandpaper, and putting a bit of white lithium grease in, they have been fine since.. Starts first time now...

Knocking on wood here !!

 

[larryw]

Same thing with a Perkins. It's almost always in the engine panel wiring/switches cause they cheap out.