Not understanding stop solenoid function

[Scott T-Bird]

I installed a Trombetta 610 pull solenoid to replace the pull to stop lever at my engine control panel. I am confused about the wiring diagram even though it would appear to be relatively simple. There are 3 wires attached to the device. White is "high current pull coil", red is low current pull to hold coil" and black is ground.

Wiring diagram appears to show a key switch that would activate the high current to pull the plunger when keyed to "start". Low current is for holding the plunger when key is on "run". It appears to me that the purpose of the plunger is to hold the fuel control "open" while starting and running and all current would be shut down, releasing the plunger when keyed to "off" This seems to make sense except that our diesel engine isn't keyed and run this way.

My key switch only provides power to a push button start. Fuel delivery is controlled by the fuel control device and fuel shut off is controlled by momentarily closing the lever assembly on the engine stop device.

So it would seem to me that if I am using a simple push button switch for fuel shut off, then I could simply provide power to the push button via the start key and when I push the shut-off button, I should be closing the circuit to the high current pull coil, which will pull the shut off lever momentarily. I release the button as soon as engine is shut down while fuel is cut off. So I should just wire the white to the shut-off switch and black to ground. When plunger is released, the shut off lever goes back to the normal position as the plunger spring returns the plunger. There isn't any use for the red wire to "low current hold coil"

Do I have this right or am I missing something?

 

[Tally Ho]

My friend has a newer Hunter 33 and he has no fuel cut-off cable. He had issues with it not running once, and it turned out to be the fuel solenoid…would not stay open when running. On his boat, turning the key on opens the fuel valve and it stays open until he hits a Stop button on his engine control panel. That closes the fuel valve and the engine dies.

So I think your understanding of how it should work is spot on…even if the application to your boat doesn’t lend itself to the solenoid.

Greg

 

[JamesG161]

Two things needed to start a diesel engine "normally".

1) Glow plug heat up. [High Amp load then for the glow plugs]
2) Fuel pump start.

To Stop the Engine
1) Turn off your key, in Neutral, should stop the fuel pump. No solenoid needed.

Jim...

 

[Scott T-Bird]

Two things needed to start a diesel engine "normally".

1) Glow plug heat up. [High Amp load then for the glow plugs]
2) Fuel pump start.

To Stop the Engine
1) Turn off your key, in Neutral, should stop the fuel pump. No solenoid needed.

Jim...

Shut off is manual. As it is, I pull a handle that is connected to a cable. The cable pulls the engine stop lever (it closes the fuel supply). Turning the key off does nothing to shut off fuel. I'm simply replacing a manual cable with a solenoid that pulls the cable.

 

[JamesG161]

I'm simply replacing a manual cable with a solenoid that pulls the cable.

Consider the loss of DC power to your fuel flow.

Jim...

 

[Captain Larry-DH]

Consider the loss of DC power to your fuel flow.

Jim...

The engine stop only needs to be momentary. Solenoids can be designed to fail open or fail closed, or latch in last state.

 

[smokey73]

Just wondering why you'd replace a manual shutoff that is nearly foolproof as long as the cable functions properly with a more complex, and albeit, potentially failure prone with a "solenoid that pulls the cable" You are effectively substituting something more complex for a simple mechanical connection. What is the gain?

 

[dlochner]

Here's a link to the installation instructions.

If I am understanding this correctly, the manual shut off is a pull connection, i.e. pull the cable and the fuel flow is physically shut off and has nothing to do with any electric fuel pump.

The drawing on the first page shows the plunger in the retracted position when on and extended when off. This would seem to be the opposite of what you want if tied to the ignition. When the key is on, the solenoid would be activated and the plunger retracted, thus shutting off the fuel supply while starting. I'm pretty certain this isn't what you want to happen.

A separate stop switch would be needed that energized the circuit when it was time to stop the engine would be needed. Probably best to make this a momentary contact switch to idiot proof it otherwise some one at some time will leave the solenoid engaged and the engine won't start and the battery will drain.

 

[Scott T-Bird]

The drawing on the first page shows the plunger in the retracted position when on and extended when off. This would seem to be the opposite of what you want if tied to the ignition. When the key is on, the solenoid would be activated and the plunger retracted, thus shutting off the fuel supply while starting. I'm pretty certain this isn't what you want to happen.

A separate stop switch would be needed that energized the circuit when it was time to stop the engine would be needed. Probably best to make this a momentary contact switch to idiot proof it otherwise some one at some time will leave the solenoid engaged and the engine won't start and the battery will drain.

I installed a momentary contact switch. It is the same type of switch used to start the engine. It has a red rubber boot to signify that it is "STOP"

To answer Jim's loss of power response. The solenoid will pull when I push the "STOP" button. That pulls the shut-off lever to cut off fuel flow momentarily. When there is no DC power (normally by releasing the "STOP" button) the spring inside the solenoid housing pushes the shut- off lever to it's normal position, which opens the fuel line.

Yes, I have those instructions and that's why I can't apply those instructions. The instructions are for a keyed ignition, and I believe it represents a situation where the solenoid has to open the fuel supply. The Yanmar ignition doesn't work that way. The key only has an ON-OFF function. The fuel supply doesn't rely on being opened upon ignition from the key.

I am only using the keyed switch to provide power to the stop button. I don't suppose it matters which post it comes from. If I connect the power lead to the DC source post, the stop switch will always have power available. If I connect the power lead to the load post, then the stop switch would only have power supplied when the key is "ON". But, to reiterate, the only reason for mentioning the key switch is because it is the only source of power at the control panel.

Power to the solenoid will only be provided when I push the STOP button. And it only needs to be momentary (not hold) because the purpose is to pull the shut-off lever. When the button is released, the spring returns the lever closed, just like I would be doing manually. It seems that I have no need for the red "hold" wire.

In an earlier thread, somebody had referenced using this same solenoid to replace the manual pull handle, so that is the generation of my question. I just want confirmation about the wiring. I called Trombetta and to my great disappointment, they said they don't have anybody available to answer my questions. They recommended that I call the supplier that I bought the part from. I had earlier called "a" supplier (not remembering who I bought it from - I'll have to search my credit receipts) and they said to call Trombetta.

 

[Scott T-Bird]

Just wondering why you'd replace a manual shutoff that is nearly foolproof as long as the cable functions properly with a more complex, and albeit, potentially failure prone with a "solenoid that pulls the cable" You are effectively substituting something more complex for a simple mechanical connection. What is the gain?

I understand your point and agree with the sentiment. The truth is, I don't like that there is so much friction in the system and the plastic casing has cracked around the handle. Lubrication would seem to be the answer but it hasn't been satisfactory. I don't like stooping over to reach for the handle and I've completely reconfigured my control panel to a position that suits me better. I simply want to eliminate that thick cable because it has made new wiring more difficult in the same run through a pedestal guard. I simply like the function of just pushing a button to stop the engine. The newer panels have this function so I figure, why not mine? I figure that a failure would be an oddity and there really isn't any inconvenience in dealing with it even if there were a failure.

 

[Claude L.-Auger]

Hi Scott,
I installed the Trombetta 610 on my 3GM30F 2 years ago. I wired it such that the Hold wire is on (+12V) when the key switch is on. The momentary "initiate" wire (white) is hooked to +12 and can take power from the always-hot starter connection . It is a fairly high ampere draw, like 10 amps. That way the stop solenoid will stay engaged until you shut off the ignition and you don't have to hold in the pushbutton until the engine stops, which may take 4 seconds or so. The "hold coil in the solenoid only draws 1 amp . The stroke of the solenoid is not a problem. The red wire coil does not have enough power to pull against the internal spring by itself so when you push the button and energize the white wire, that coil pulls the plunger back and then the red wire coil can hold it (with the button not pushed) until the engine stops. You don't have to hold the stop button but only have to activate it momentarily. It will hold until the key switch is turned off. If the engine has to be restarted quickly, the key might have to be turned off then back on to release the plunger.
Be careful to use a push-on momentary button with enough amperage. My first one, nice and fancy but low amps, got singed in a matter of 3 weeks! I have since installed a high-amp truck starter button. Works like a charm.
Hope that helps. Good luck

 

[Scott T-Bird]

Thanks Claude,

So that sounds even better. I don't have to worry about the hold position running the battery down, either, because whenever the key is on (with engine off), that awful buzzer is blaring!

 

[Mark Maulden]

I had a solenoid fail on my beta 35 (400 hrs). I'm going to hook up the mechanical one as a backup. The old green machine had one and with a longer cable, I can easily repurpose the install.

 

[Tally Ho]

Just curious now….if the solenoid fails or you don’t have 12-volt power for some reason, what happens?
-What happens if the engine is already running….?
-Can you start the engine (probably not with no power…) but what about if the solenoid fails?

I keep thinking about the solenoid on my propane system…which shuts the valve if there is no power…I would not want that to happen with my engine at a time when I really need it.

I cannot help but think that this is making a pretty simple device a lot more complicated and prone to failure.

I like to think that my little old 2GM20F with essentially no electronics can still help me escape when the big EMP strikes

Greg

 

[Scott T-Bird]

Just curious now….if the solenoid fails or you don’t have 12-volt power for some reason, what happens?
-What happens if the engine is already running….?
-Can you start the engine (probably not with no power…) but what about if the solenoid fails?

I keep thinking about the solenoid on my propane system…which shuts the valve if there is no power…I would not want that to happen with my engine at a time when I really need it.

I cannot help but think that this is making a pretty simple device a lot more complicated and prone to failure.

I like to think that my little old 2GM20F with essentially no electronics can still help me escape when the big EMP strikes

Greg

Nothing changes for the starter so starting the engine is not affected by adding a solenoid for stopping. If the solenoid fails, I would reach inside the engine compartment and push the stop lever to stop the engine. Very simple. I thought about keeping the mechanical cable for back-up but I would still want to relocate it. What I want to do is eliminate the cable run that goes inside one leg of the pedestal guard. I don't like this location.

 

[Benny17441]

Love mechanical simplicity whenever it is available. A cable about to break will usually give you some notice as it stretches, but a solenoid can and will fail at any time without any warning. It is easier to schedule a preventive cable replacement at the dock than to deal with a failed solenoid in the middle of a trip. I know a shutoff solenoid will not present a major problem but other electrical convenience parts may.

 

[Claude L.-Auger]

While I do agree that the cable being mechanical is supposedly trouble free, in my case 4 times (yes 4 times) I have had to change the cable and the plastic Yanmar panel because 4 times a guess (4 different ones) wanting to step down on the cockpit floor from the port seat hit it with his heal, bent the cable and broke the panel. I relocated the cable under the starboard seat but it was inconvenient as hell. Cost of cable + cost of panel (type-B) X 4= about 4 times cost of solenoid and momentary switch ! If ever a problem arises, I can still kill the engine by pushing on the lever that the solenoid is connected to. Plus, I left the cable in place and would only have to reconnect it to the lever to make it functional. So far, I love my new puch-button kill switch. And Scott is right, that annoying oil pressure alarm stays on until the key is turned off, so that is conducive to not leaving key on with engine shut down.