Q: Energize to stop or energize to run solenoid

[Searios]

Hi All,

Any recommendations, experiences or problems with the "energize to run" or "energize to stop" solenoids? What is the best type?

I vaguely remember there was a short discussion or document about an owner who bought a Perkins (I think) - he had a problem due to the solenoid - but I can't find the document.

 

[bobofthenorth]

I wouldn't let it determine my decision to buy a particular diesel but when I rewired the control circuit on the Onan in my bus I went with energize to run. That was the simplest concept for me to understand. I ran the ground to the solenoid through a normally closed temperature switch and ran the hot through a normally open oil pressure switch. If it gets hot it loses its ground and if it loses oil pressure it loses the hot connection. That was about as simple a solution as my brain could come up with. In my world if the stuff hits the fan I want the engine to stop. For me it comes down to how closely the engine is monitored by a human being. The Lehmans on Gray Hawk are energize to stop but I'm standing there watching them all the time. The generator on the other hand runs away by itself - ideally without any user intervention ever.

 

[Larry H]

If the engine is a mechanical injection like a Lehman, I would want the solenoid to be 'energize to stop'.

I don't want to have an electrical failure stop a running engine. On the Lehman, the solenoid operates an exposed lever. That lever could be actuated by hand to shut off the engine if the solenoid fails.

 

[psneeld]

If the engine is a mechanical injection like a Lehman, I would want the solenoid to be 'energize to stop'.

I don't want to have an electrical failure stop a running engine. On the Lehman, the solenoid operates an exposed lever. That lever could be actuated by hand to shut off the engine if the solenoid fails.

Tend to agree...my last diesels were Cat 3208s with energize to run.

I know of dozens of 3208 owners that have been instructed by CAT mechanics how to bypass that to get somewhere...

 

[Moonstruck]

If the engine is a mechanical injection like a Lehman, I would want the solenoid to be 'energize to stop'.

I don't want to have an electrical failure stop a running engine. On the Lehman, the solenoid operates an exposed lever. That lever could be actuated by hand to shut off the engine if the solenoid fails.

Energize to stop. Had a solenoid go out on my Blackfin's 3208. Just took the solenoid off and pushed the lever to stop the engine. Better than not being able to start it.

 

[bobofthenorth]

I know of dozens of 3208 owners that have been instructed by CAT mechanics how to bypass that to get somewhere...

Exactly. If the object is to jury rig something that will get you home then it doesn't make any difference whether you have to go to the engine room to start the engine by tying the rod open or whether you have to go to the engine room to stop the engine by pushing the rod closed. My point was that if something fails then an energize to run system is pretty simply set up to shut things down. I'd rather have an unplanned shutdown than keep running a dry Lehman until it warped the head and blew a head gasket. Not that that ever happens to anybody, but just in case.

 

[Searios]

This is a mechanical engine.

 

[Marin]

In our boat there are no stop solenoids. Instead there are a pair of fuel shutoff knobs on Teleflex cables that you pull up to shut off the fuel to the engines. When the engines have stopped you push the knobs back down so the engines are ready to start next time.

So our shutoff controls are not "energized" until we pull them up to shut off the fuel. If we were to convert to solenoids we would want the same thing. The solenoids do nothing until we want to stop the engines. At that point, push a button, solenoids move the fuel cutoff lever to "cut off," engines stop, release the button, engines are ready to start and run again.

 

[Keith]

Energize to stop, especially if you have a single. I'd much rather have to go down to manually stop the engine than have it quit on me in the middle of traffic.

 

[Peter B]

One other possible issue is the constant, albeit small, current drain keeping an 'energize to run' set-up going, and I've noticed an open solenoid actually gets quite hot..and often you run a diesel boat for literally hours or even days at a time. Compared to the actual time needed to actuate to shut down, it seems hardly logical to have anything other than 'energise to shut down'...just a thought.

 

[FF]

Any recommendations, experiences or problems with the "energize to run" or "energize to stop" solenoids? What is the best type?

NO SOLENOID , the pull cable is far easier to operate , trouble shoot , or replace.

KISS is never a mistake.

One thing the Coastie's require on inspected boats is a pull cable to turn off fuel AT THE TANK.

Not for stopping the engine , but for keeping a small fire from getting big , or a fuel pipe or filter to bilge leak from emptying the tank.

Usually this is an easy and cheap retrofit for most boats.

 

[CPseudonym]

I'm having a difficult time following this thread. Are you discussing the difference between "normally open" and "normally closed" solenoids in the fuel supply line to the engine?

 

[Marin]

I'm having a difficult time following this thread. Are you discussing the difference between "normally open" and "normally closed" solenoids in the fuel supply line to the engine?

Yes. At the risk of telling you what you probably already know, older systems like ours have a simple Teleflex cable that connects to the fuel shutoff lever on the injection pump. This lever is normally left in the open position. Pulling up on the knob at the helm moves the lever to the shutoff postion and the engine stops. Pushing the knob back down moves the shutoff lever back to its open position.

But newer boats tend to have a solenoid that operates the shutoff lever. So the question being asked is which is better--- to have a solenoid that is energized to open and hold open the shutoff lever, or to have a solenoid that is energized to close the fuel shutoff lever?

In the former, energizing the solenoid would move the lever to its open position and hold it there for as long as you wanted the engine to run De-engergizing the solenoid would cause it to move the shutoff lever back to the no-fuel position.

The latter would be just the opposite. The shutoff lever would normally be in its open or run position. Energizing the solenoid would move the lever to its closed or shut off position as long as the solenoid was energized. De-energizing the solenoid after the engine had stopped would return the shutoff lever to its open position.

 

[Peter B]

My old 1975 era L120 had a lever, but clearly had a solenoid fitted later. I like the push button solenoid activated shut-down, because the lever, whilst still in place, comes out of the top front edge of the galley bench, just above the frig door, and frankly, while that made for a short cable run, is not a convenient place to reach for, especially while trying to turn the key off in the dash over in front of the helm position to shut down that loud oil low warning buzzer that is immediately triggered. Where are your lever knobs, Marin..?

 

[FF]

that loud oil low warning buzzer that is immediately triggered

And your problem with checking a safety system on shutdown is?

 

[Phil Fill]

Any recommendations, experiences or problems with the "energize to run" or "energize to stop" solenoids? What is the best type?

NO SOLENOID , the pull cable is far easier to operate , trouble shoot , or replace.

KISS is never a mistake.

One thing the Coastie's require on inspected boats is a pull cable to turn off fuel AT THE TANK.

Not for stopping the engine , but for keeping a small fire from getting big , or a fuel pipe or filter to bilge leak from emptying the tank.

Usually this is an easy and cheap retrofit for most boats.

We have had several inspections and a pull capble turn off at the fuel tank has not been mentioned. Maybe the reason is the fuel is drawn from the top of the tanks, so if there was a break the fuel would drop back into the tank and if the engine is not running then fuel would not be drawn/sucked. Each tanks does have a shut off valve for both the draw and return. I do not understand what a pull cable fuel shut off at the tank would do?

We were required by the insurance company to install an automatic shut down on the gen set if the Hylon system went off as the gen set can be left running with not body on the boat. However, was not required on the main 671, the reason is that when the main engine is running normally somebody would be on the boat.

The gen set has a DC on solenoid that I have wired around, so the Perkins engine can be started by passing the DC electric shut down. Since the gen set drives the hydraulic for the bow thruster and/or get home, I do not want the engine to shut down unless I manual shut it down. The same is true of the main 671. Both have gauges and alarms that sound.

 

[SomeSailor]

Mine are wired to "energize to stop". This reduces chance that a dead battery or loss of voltage would leave me without maneuverability.

Like said above, I could always shut them off by pulling the levers.

 

[Marin]

Where are your lever knobs, Marin..?

They are located on the helm console adjacent to the power lever and shifter Morse boxes. You can see them in the photo below. The identical Teleflex knobs behind (forward of) them are the cold-start controls.

The push button between them is for the dual air horns. This photo was taken a few years ago; the white Icom VHF has since been replaced with a newer model in dark gray.

 

[FF]

We have had several inspections and a pull capble turn off at the fuel tank has not been mentioned.


Inspections by the USCG to carry more than 6 pax?

 

[rwidman]

I think the "energized to stop" option is the safest of the two. While a solenoid or electrical failure would leave you having to find an alternate way to stop the engine, it won't leave you with a dead engine while you're drifting towards a bank of rocks or other boats.

 

[Codger2]

Mine are wired to "energize to stop". This reduces chance that a dead battery or loss of voltage would leave me without maneuverability..

 

[BobH]

I agree with "energize to stop", it is to me the preferred setup. When we brought our just purchased boat home it turned out that neither alternator was working so we gradually lost all DC power but the engines kept running. When we got to the slip we couldn't stop the engines without DC power but at least we got there.

Bob

 

[timj]

Hi


Our Cat 3208 NA is wired "energize to run". How do I change to "energize to stop".

I presume I need a new solenoid and if so where would I source one of these?

Grateful any advice please.

 

[Tomicue]

My solenoids are energized to run but when the engine gets hot the solenoid looses it's magnetism, can u adjust this or does it need replacing? I currently have removed it and shut the engine off my pulling the lever

 

[FF]

I currently have removed it and shut the engine off my pulling the lever

Use an outboatrd cable to push pull the engine stop to the bridge , problem solved.

 

[rwidman]

My solenoids are energized to run but when the engine gets hot the solenoid looses it's magnetism, can u adjust this or does it need replacing? ...............

The solenoid gets it's magnetism from the DC current passing through it. If there's the same voltage at the solenoid terminals when the engine is hot as when it is cold, replace the solenoid. If it's lower, find out why. If the solenoid has only one wire and relies on the mounting screws for a DC ground, that would be the first place to check. Unscrew it, clean the mounting surfaces, and reinstall it. Tight.

 

[Tomicue]

Cheers Ron ill give it ago

 

[Craig Schreck]

On engines that have external levers on the fuel pump I think a energize to stop is best, just one less electrical load during start up, then back it up with a simple pull cable and your bullet proof, Yanmar stop cables are cheep and real flexible its a easy install. On some engines like the B Cummings you have to apply voltage to run the sol is internal so you have no choice it shuts down when you turn off the IGN key.