Odd Yanmar issue

[Tally Ho]

Probably added by a PO.
Can you determine the brand? Maybe a model #.

That would allow you to contact the mfg, or maybe someone has a similar model owners manual to share.

But, if you found the so,Union (the override switch), I would be inclined to use that when needed and leave well enough alone. Good that you found the override before you really needed the engine after a discharge.

My old boat has a haylon cylinder, and a heat activated discharge valve of some sort. But no electrical connections that interlock with the engine. The discharge valve does have 2 wire connections, but they are not connected to anything.

I don’t know what would happen if you just disconnected any wires to the suppression device.

Glad you figured out why it wouldn’t start.


Greg

 

[George Braun]

Probably added by a PO.
Can you determine the brand? Maybe a model #.

That would allow you to contact the mfg, or maybe someone has a similar model owners manual to share.

But, if you found the so,Union (the override switch), I would be inclined to use that when needed and leave well enough alone. Good that you found the override before you really needed the engine after a discharge.

My old boat has a haylon cylinder, and a heat activated discharge valve of some sort. But no electrical connections that interlock with the engine. The discharge valve does have 2 wire connections, but they are not connected to anything.

I don’t know what would happen if you just disconnected any wires to the suppression device.

Glad you figured out why it wouldn’t start.


Greg

in original equipment from Hunter, most of their larger boats have one. Actually connected yesterday with Sea-Fire, the system manufacturer and got great and detailed suggestions as to what to look for to diagnose. Their electrical design guy echoed my thought that it's probably a conductivity/grounding issue and showed me what to disassemble and clean to hopefully fix. easy

 

[Tally Ho]

in original equipment from Hunter, most of their larger boats have one. Actually connected yesterday with Sea-Fire, the system manufacturer and got great and detailed suggestions as to what to look for to diagnose. Their electrical design guy echoed my thought that it's probably a conductivity/grounding issue and showed me what to disassemble and clean to hopefully fix. easy

Still seems odd that your electrical, problem ONLY shows up when on the hard…

Let us know when you get it figured out.

Greg

 

[quadrille38]

Yes factory installed. You might find a loose connection that is making it not allow engine to start. I had a Dripless shaft seal installed a few years ago and in the course of things a wire got removed from the suppression system, It prevented the engine from starting. Plugged back in and eng fired right up.

 

[Scott T-Bird]

How do these fire suppression systems actually work? We know that when triggered it doesn't disengage the starter. So, does it cut off fuel flow with a valve that closes the fuel line or does it decompress the cylinders somehow? I can't imagine that it cuts off air flow ....

 

[George Braun]

When the system detects a heat event the fire suppression agent is dispensed, and a relay engages to prevent the engine start circuit from activating. Old days the fire suppression agent was Halon. My issue is almost certainly either a connectivity issue or a control relay that needs replacing.

 

[Scott T-Bird]

When the system detects a heat event the fire suppression agent is dispensed, and a relay engages to prevent the engine start circuit from activating. Old days the fire suppression agent was Halon. My issue is almost certainly either a connectivity issue or a control relay that needs replacing.

I understand that it is an electrical condition that interrupts the ability to start the engine. What I am asking is ... how does the fire suppression system prevent the engine from firing? You say that the starter engages but the engine doesn't fire. As @ggrizzard says, it's either fuel, air or compression that is missing. I'm just curious which is denied? I suppose the simplest way is the suppression system engages a solenoid that pulls the stop lever, thus starving the engine from fuel. It must be like attempting to start your engine with the stop handle fully pulled out. I've done that more than a few times at the fuel dock! ALWAYS gets a reaction from Sue ... usually some reference to "Captain Kangaroo"

 

[George Braun]

i'm fairly sure that the control relay disables the starter. there isn't any connection to the fuel system that I can see. Fire bottle with heat detection element in the engine space, and a control relay behind the starter panel. that's all there is.

 

[Scott T-Bird]

i'm fairly sure that the control relay disables the starter. there isn't any connection to the fuel system that I can see. Fire bottle with heat detection element in the engine space, and a control relay behind the starter panel. that's all there is.

I don't mean to stray too far off the topic of the thread, but I still don't really understand how the starter would be disabled when you said that the starter spins but the engine doesn't fire. That doesn't sound like the starter is disabled. It is understandable that the electrical circuit could be wired to the starter to set off a sequence that would disable the engine when a fire sensor is triggered by a fire (but I don't envision it).

Also, what if a fire starts as the engine is running? Disabling the starter isn't going to shut down the engine. What, exactly, causes the engine to shut down in the event of a fire, or what prevents it from starting when the starter is spinning? I'm only guessing, but I would assume that the fuel flow is shut off somehow.

 

[quadrille38]

I don't mean to stray too far off the topic of the thread, but I still don't really understand how the starter would be disabled when you said that the starter spins but the engine doesn't fire. That doesn't sound like the starter is disabled. It is understandable that the electrical circuit could be wired to the starter to set off a sequence that would disable the engine when a fire sensor is triggered by a fire (but I don't envision it).

Also, what if a fire starts as the engine is running? Disabling the starter isn't going to shut down the engine. What, exactly, causes the engine to shut down in the event of a fire, or what prevents it from starting when the starter is spinning? I'm only guessing, but I would assume that the fuel flow is shut off somehow.

I’m not sure if this will help you but from my owners manual here is a schematic of the fire suppression system that is installed on my boat.

 

[ggrizzard]

Caveat:
*I know nothing about the engine or the fire suppression system under discussion*
Here's an idea:
If the system being discussed is somehow tied to the compression relief valves,
the engine would turn over but not start.

 

[MitchM]

If I was in jail in a foreign land, and getting free depended on my solving why your engine would nt stay running because of that halon thing, I d Be in jail for a long time.

 

[Scott T-Bird]

I’m not sure if this will help you but from my owners manual here is a schematic of the fire suppression system that is installed on my boat.

View attachment 222640

I guess the key would lie in where that white/brown wire leads (purple if a Volvo engine).
It doesn't look to me like there is any interruption at the ignition switch.

 

[quadrille38]

I guess the key would lie in where that white/brown wire leads (purple if a Volvo engine).
It doesn't look to me like there is any interruption at the ignition switch.

Doing some additional searching for information to help you. Found this in more of my manuals. Not certain but it sounds like if the suppression system discharges it disables the exhaust blower and stops the engine. The engine on my boat does not have a pull lever engine stop. It has a stop button at the panel so would it make sense that the suppression system is tied into the same circuit that is used to stop the engine?

 

[Claude L.-Auger]

If your engine has an electric stop button, it would be a simple matter for your fire suppression system to be connected to it thus preventing the engine from firing but letting the starter spin, much like what Scott T said while trying to start with the engine stop cable pulled all the way out. The question still remains though as to why it would do that while on the hard and not while in the water?

 

[quadrille38]

If your engine has an electric stop button, it would be a simple matter for your fire suppression system to be connected to it thus preventing the engine from firing but letting the starter spin, much like what Scott T said while trying to start with the engine stop cable pulled all the way out. The question still remains though as to why it would do that while on the hard and not while in the water?

perhaps a short as OP questioned. Or perhaps the gas pressure in the suppression system is marginal and in the cooler fall weather it’s registering too low thereby triggering a no start condition.