As you face the engine there is a large relay made by valeo to the left of the alternator.
Both the start and stop solenoids get their battery ground from this solenoid when it is closed.
On one side of the valeo there is a large stud on the solenoid and should have a Very heavy black cable which connects directly to the starter battery. You can check the battery connection between this cable and the red battery cable on the starter motor with a voltmeter.
The other large stud should have a heavy gauge black wire that along its length around the back of the engine and has all the negative connections for everything on the engine ( numerous soldered connections and gooey electrical tape). It ends at the negative pole on the Yanmar small alternator.
Try depressing the black button down on the valeo and while holding the button down have someone else try starting the engine and stopping the engine.
I think that will solve the problem. Just make sure the valeo solenoid engages when you try to start or stop. If it does and the engine still does not start / stop then the solenoid should be taken apart and have the contacts cleaned. If the solenoid does not try to engage- you will feel this through the body of the solenoid. You then have a break in the wiring to the solenoid. If you feel it try to engage with the start button and not with the start key then it is the start key and a bad solenoid and vice versa.
Further electrical info. From the valeo solenoid under heat shrink tubing there are diodes to prevent the engine starting and stopping at the same time.
You could have a bad diode—I doubt that.
To the left of the valeo solenoid is another black Yanmar solenoid that is wired to the valeo and then runs to the solenoid on the starter motor. This solenoid is powered by the panel start switch (red wire) and the negative is connected to the Valeo solenoid via the smaller black wire.. The stop solenoid in the fuel injector pump is connected to the stop button on the panel and is also connected to the valeo solenoid thus the need for the diodes.
I know this is complicated but the fellow who originally wired the engine is being released from the Psychiatric hospital in 2 months.
However if you can’t wait for him,
I can help you if you will be in SXM late afternoon on the 14 of this month and I will be on board for a week.
Simpson Bay Marina slip C14.
I am in NY and the boat is in SXM. However this wiring is burned in my brain.
Kimberlite Amel Super Maramu #376
I have starting and stopping issue with my yanmar 4-JH3-TE. It begin with stop button failure then progressed to intermittant starter failure and now total failure of starter to engage. Because of timing I feel they are related.
After Initially troubleshooting the connections and cleaning them I checked out the stop button with multi meter and I determined it was good but ignition switch was sending only 6 volts to button. I assume stop solenoid needs at least 10 volts to work? There is 12 volts coming into ignition switch.
In any event , I moved on to more pressing start issue.
By clicking key on and off I was get it to spin. Now all I get is clicking at the small green relay attached on starboard side of motor. ( I seem to have three solenoid or relays/. One on the starter, one attached to motor and another relay or solenoid attached to motor which gives me the click.
After bad connection my first thought was faulty relay or solenoid now thinking maybe ignition switch corroded and not providing voltage to starter solenoid or stop switch.
I would appreciate amy and all suggestions
Ben and Gayle
La Bella Vita
Currently St. Martin