Yanmar Fuel Shut off Solenoid

[Diverrob]

Hey everyone

I have a couple questions that I need help answering if you don’t mind. First the engine I have in my 34’ 2007 Mainship Trawler is the Yanmar 6LPA-STP. I have an issue with shutting down the engine from the ignition switch. It’s a three way switch which is normally in the run (middle) position you push up to start and down to shut off. It starts and runs fine however pushing down on the switch does nothing. The only way I can shut down the engine now is to cut power to the circuit at the breaker panel. What I want to know is if the solenoid uses power to keep the fuel open or does it use power only to shut it down. I think the solenoid must be working because the engine starts and runs perfectly fine and when I cut power it shuts down immediately so I think it’s a switch/power issue. Also if anyone has a picture of where it is located exactly that would also be helpful (I have looked and think I know where it is but want to be sure). Thanks

Rob

 

[Chrisjs]

I used to have a 65HP Yanmar as a back-up wing engine. While it was set up for starting from the pilot house, the only way to shut it down was a manual (pull cord) in the engine room, presumably attached to the fuel solenoid. No idea why it was rigged this way and as a back-up it was not really an issue, but perhaps you have a similar install.

 

[Diverrob]

I used to have a 65HP Yanmar as a back-up wing engine. While it was set up for starting from the pilot house, the only way to shut it down was a manual (pull cord) in the engine room, presumably attached to the fuel solenoid. No idea why it was rigged this way and as a back-up it was not really an issue, but perhaps you have a similar install.

No I don’t think mine is the same, it used to shut down using the ignition switch on the console. Thanks

Rob

 

[Olebird]

Diverrob,


I have the same engine in my 2003 MS Pilot 30 II. The operating manual and service manual are on line. The schematic shows the valve schematically as a normally energized solenoid, de-energized by the stop switch. Unfortunately no drawings show it's physical location. I'm not at the boat, but it's got to be in the fuel line somewhere before the injection pump. Only owned this boat since October and have not had much time to learn the engine in detail. If you find it before I do - post a photo pls.


Thanks
Larry

 

[Long Island Boater]

It sounds like the stop relay or the solenoid is bad. There’s a small 1.5” square brown relay responsible for shutting down the solenoid. The relay is cheaper of the two so test that first. Look on the starboard side of the engine near the on-engine fuel filter. You will likely see a couple of cable ties securing it in place. There’s an easy way to test if it’s the relay. The next time the engine won’t shut down from the helm, you can manually operate the solenoid by squeeze the rubber boot for a few seconds. The engine should shut right down. If that doesn’t work, it’s the solenoid. Could be both but more likely one or the other.

 

[Capt Easy]

I was having the same issue on my 4jhte. Mine ended up being the plug connector to the shut off solenoid, located on the injection pump.

The plug is located under the oil dipstick and according to BoatDiesel.com, it seems to be a common problem of oil dripping into the connector, causing a poor connection.

I disconnected the plug, sprayed it with Corrosion Block, cleaned it best I could and that fixed my issue. Not sure if it’s the same setup on yours.

 

[Marlinmike]

The 6LP has the stop solenoid in the injection pump and it needs 12vdc to run. you can put a meter on the plug and see what is happening.

I had that issue, power did drop off on shut off of key yet still ran, sometimes after a few minutes it would shut down and this only happened when the engine was hot, if start cold it would shut right off. I changed fuel back to Valvtec and the problem went away. So there must be something sticking.

 

[Diverrob]

Thanks for all the input so far, I had the chance a few weeks ago to do a bit of trouble shooting and found this.

Power to the solenoid is obviously there as the engine starts and runs fine. When I disconnect the plug to the solenoid the engine stops so I thought it was the switch at the helm. Pulled the switch and checked it with a meter and everything checked out ok.

Now I’m not sure where to look, is there another relay between the helm switch and the solenoid? The same thing happens when using the shutoff switch on the upper helm as well so there must be something in between that I’m missing.

I will keep looking as I have time (currently working out of town). Thanks again

Rob

 

[Marlinmike]

I believe there is a relay, just not sure which one ( a few on the back of the inner cooler), I don't have my manual handy otherwise I'd look it up.

 

[Cigatoo]

My 4LH had a square black relay. The prongs on the relay needed to be cleaned yearly. The relays and wire harness seem to be added after the fact. I have found them in various locations on other Yanmars. Usually held on with wire ties. Start at the stop solenoid and follow the harness back.

 

[Began]

How about this- The 6LP stop solenoid is open (energized) to run. As you say- you shut off the power it kills the engine. How about pulling off the connector at your 3 way switch and see if it stops the engine? If it does the problem is that 3 way switch?

 

[Diverrob]

How about this- The 6LP stop solenoid is open (energized) to run. As you say- you shut off the power it kills the engine. How about pulling off the connector at your 3 way switch and see if it stops the engine? If it does the problem is that 3 way switch?

Ok thanks for the tip, I will give it a try but if there is a relay between the switch and the solenoid and the relay is faulty then this won’t confirm the switch is bag or good. Still worth a try though

Rob

 

[LongJohn]

On my Yanmar 6LYA, the secondary circuit of the fuel shut off relay is not energized in "run". The secondary relay circuit is energized by the Stop switch, and is energized as long as the Stop switch is held. The relay primary circuit feeds the fuel shut off solenoid. My fuel shut off solenoid appears to have been replaced by TPO. I've had to replace the relay twice.

 

[Diverrob]

On my Yanmar 6LYA, the secondary circuit of the fuel shut off relay is not energized in "run". The secondary relay circuit is energized by the Stop switch, and is energized as long as the Stop switch is held. The relay primary circuit feeds the fuel shut off solenoid. My fuel shut off solenoid appears to have been replaced by TPO. I've had to replace the relay twice.

I am trying to find the relay, the solenoid seems to be functioning fine. With the engine running I can shut it down locally at the engine by pulling the plug leading to the solenoid (killing power). There must be a relay that both the upper and lower bridge switches connect to but I can’t seem to find it at the moment.

Rob

 

[Began]

LongJohn- this is a 6LP.
DiverRob- wiring diagram attached for a "C" type panel

 

[Ski in NC]

6LP is not like the 6LY or 4JH. LP solenoid is screwed into the inj pump and is energize to run. LY and JH solenoid is external to pump and is energize to stop.

To find out if it is a sticky solenoid, get someone to hit stop button/switch/whatever and see if volts vanish from solenoid terminal. I don't think there is a relay involved like there is on the LY and JH (from current pull consideration). Could be wrong, though.

 

[Diverrob]

6LP is not like the 6LY or 4JH. LP solenoid is screwed into the inj pump and is energize to run. LY and JH solenoid is external to pump and is energize to stop.

To find out if it is a sticky solenoid, get someone to hit stop button/switch/whatever and see if volts vanish from solenoid terminal. I don't think there is a relay involved like there is on the LY and JH (from current pull consideration). Could be wrong, though.

I will give that a try but when i cut power from the breaker panel or pul the plug locally at the solenoid it stops immediately every time. I will put a meter on it though and see what happens. The thing is that both the upper and lower helm are reacting exactly the same. That is why I was thinking there was a relay between the solenoid and the helm switches.

 

[Began]

Part # for that relay is 119773-91850...looks like any other cube relay but I can't find the location.

 

[Diverrob]

Part # for that relay is 119773-91850...looks like any other cube relay but I can't find the location.

That’s very helpful, thanks at least I kinda know whet I’m looking for now

 

[Diverrob]

Part # for that relay is 119773-91850...looks like any other cube relay but I can't find the location.

Ok found the relay and there was quite a bit of corrosion around most of the terminals. I cleaned them up but no joy so I will try and source a new one and see if that’s the issue. Thanks again for your help.

Rob

 

[Diverrob]

Ok so I have a new solenoid however that was not the issue as it’s doing the same thing (not shutting down). I did discover one thing however, if I disconnect the wire that supplies power to the fuel shutoff solenoid (purple one) on either of the switches (upper or lower helm) then the other switch works as it should shutting down the engine. Once I connect them both back neither of them work. I have attached a picture of the underside of the switch (both are exactly the same). The red wires are positive and always hot when the breaker is on. The yellow one goes to the starting solenoid and is only hot when you press the switch to start the engine. The purple one is hot all the time and supplies power to the fuel shutoff solenoid, this one is interrupted when you push the switch to the stop position cutting power to the solenoid. The relay sits in between the fuel shutoff solenoid and the switch and I assume will allow either the upper or lower helm to start or stop the engine (I have replaced it with a new one). If anyone can help me trouble shoot this I would appreciate it, thanks.

 

[Diverrob]

So I figured it out finally ? apparently you need to start with both the upper and lower switches in the off position. Then chose which position you plan on using and flash up from that station. As long as the one of the switches are in the off position then the other one will work as it should. If this is the way it was designed it seems strange as you can only shut the engine down from the position you started from unless you run up and down a couple time moving the switches to that one is in the run position and the other is off. Does anyone know if there is a way to make this easier, possible install a diode on the switch??

Rob

 

[J.Metzler]

Having the same trouble, not shutting down

My 6lpa on my mainship not always hitting down. Corrosion issue??

 

[BWunderful]

Where did you find the relay? I’m having a similar issue on my 6ly2a. Ute. And it’s not marked in the tech manual or the parts manual.

 

[Diverrob]

Where did you find the relay? I’m having a similar issue on my 6ly2a. Ute. And it’s not marked in the tech manual or the parts manual.

I believe I got it at our local auto shop, it’s not specific to Yanmar and has a part # or diagram on the part. I believe it was a fairly common part an did not have difficulty finding one locally.

Rob

 

[BWunderful]

Thanks. I was actually wondering where the relay is located in the boat. I wasn’t able to find one on the engine. Took a picture of the area. I’ve got a terminal hanging loose - wondering if there’s supposed to be a relay on there.

 

[Diverrob]

Mine was in the port side of the engine just below the oil filter