Isolated ground solenoid

Eric Freedman

The negative attachment is on the big stud to the left. The Positive for the meter is the stud on the valeo with the orange and blue wire (start and stop) note there is a small black wire sneaking behind the Valeo connected to the battery stud connection--that is the negative connection that actuates the solenoid-- always connected to the battery

On July 5, 2020 at 3:25 AM eric freedman <kimberlite@...> wrote:

Hi Mark,
The Valeo solenoid works to both start and stop the engine.
It is isolated by a pair of diodes. One is fed by the start key and the other is fed DC from the stop button Without the Motorola diodes the engine would try to start and stop at the same time. The function of the Valeo solenoid is to temporarily connect the engine block to the battery negative for both starting and stopping the engine. the stop solenoid in the fuel injector pump and the starter motor are operated by their respective buttons and are really not Toms problem. His problem is that the Valeo Solenoid is not closing to ground the block.
Fair Winds,
sm 376

Pardon my typing and speling. I tore tendons off the bone in my right arm when we were knocked down flat by a microburst. last winter They just reattached them last week. It was amazing we were sailing along in clear cloudless air and bam in a second Kimberlite had he sails in the water. I ripped the tendons off trying to cranking the mizzen after releasing the genoa.

On July 5, 2020 at 12:54 AM Mark Erdos <mcerdos@...> wrote:



In addition to the great advice from Eric, be sure to take a look at the stop solenoid. This is often overlooked when dealing with a start issue.



With best regards,





Sailing Vessel - Cream Puff - SM2K - #275

Currently cruising - Tahiti, French Polynesia


From: [] On Behalf Of eric freedman
Sent: Saturday, July 4, 2020 4:33 PM
Subject: Re: [AmelYachtOwners] Isolated ground solenoid



Before you start chasing zebras, try these simple tests.

Does the engine start id you depress the valeo solenoid and someone tries to start the engine?

If you are able to start the engine then try the following.

Measure the voltage at the engine between the power + wire to the valeo solenoid and the battery ground when someone tries to start the engine.. IF you get 12.5 volts + then there is a problem either with the valeo solenoid or the yanmar black solenoid mounted next to the valeo solenoid.


If you do not get 12.5+ volts then there is a problem with the red wire from the panel. Look at the yanmar B panel wiring diagram.


The red wire is a wire going from the Yanmar engine panel to a 3 wire harness. The wire is Red but it might be spliced into a white wire.

Remove the Yanmar panel and look behind it for a solderless crimp connector joining the 2 wires.

It is about 1 foot from the panel down in the mess of wires. If you have that connection remove it and solder the wires together. That is the wire that both closes the valeo solenoid and starts the engine.


That wire runs to the smallest of the 3 harness connectors at the engine Starboard side possibly under the insulation. There is a red, blue, and white wire on the 3 wire connectors. Open it up and spray it with corrosion x. 


I would love to know what you find.

The valeo is just an expensive starter motor solenoid for 12 volt vehicles. . What makes it different is the back actuator button.


If you have an automobile starter solenoid make it is an isolated ground solenoid. If the negative wire is connected to the metal body of the solenoid it is not isolated ground and defeats the Amel bonding.

It could be an internal connection.  It is a great spare to have.


The 24 volt valeo solenoid if for the genoa furler mounted most forward port side forward cabin.

The Valeo 12 V solenoid is 160 euros and the Auto version is about $20- Thats a lot of money for a rubber button

Where are you located?

Fair Winds,


SM 376


Ps do you have a switch mounted in a white plastic perforated box outboard of the engine stringer and forward of a Calpeda AC pump? It is for a high water alarm. If you have this switch please see if you can identify the maker or at least send me a photo with measurements.

somehow the top 1/2 of that switch disappeared on Kimberlite. 




On July 4, 2020 at 5:46 PM Thomas Kleman <lorient422@...> wrote:

So, engine doesn't start intermittently. After corrosion x in the solenoid, cleaning contacts, problem re-emerges. Can start engine by pushing button but need to fix this. Broke out spares purchased across the years and noticed my spare solenoid is 24 volt (need a 12 volt). I have a Cole Hersee 12 volt solenoid (no button) but am not sure if the wiring relating to the "s" and "I" marked small terminals on the solenoid relative to the red and black wires on the existing valeo solenoid. Any thoughts ? Internet research suggests red to "I" but I'm not confident enough to do it. Of course will order correct solenoid when possible.

Tom and Kirstin
SM2K 422






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