Turning Off Your Diesel Engine

[psneeld]

Depends on how the engine starter and alternator are wired. My alternator output is wired to the starter hot terminal so the alternator is always connected to a battery.

I do have a batter isolate switch, but the only time that would be used would be in a fire or starter runaway situation.and at that point if the house bank is connected, I won't fry the alternator.

But again, a person could have a zap stop on the alternator to even prevent that.

We can all say what OUR setups are and how to manage them, but we are clueless about the OP's and how he should manage his.

 

[High Wire]

Do what the OP manual says.

Warning Thread Drift.

PS out of curiosity, I looked at what mine (Perkins 6.354) said for starting. It says to advance the throttle to MAXIMUM then start the engine, then bring it down to idle.
I advance it a little, but never WOT. Always starts right up.
Anybody else starting at WOT? Am I actually hurting my engine by trying to be gentle with it?

 

[Bacchus]

Depends on how the engine starter and alternator are wired. My alternator output is wired to the starter hot terminal so the alternator is always connected to a battery.

I do have a batter isolate switch, but the only time that would be used would be in a fire or starter runaway situation.and at that point if the house bank is connected, I won't fry the alternator.

But again, a person could have a zap stop on the alternator to even prevent that.

We can all say what OUR setups are and how to manage them, but we are clueless about the OP's and how he should manage his.

Is it only the Alt output that is a concern re shutting off while running?
I thought there is also a concern for breaking the external sensing / excite wire to the Alt also?
However... I'll admit I'm no electron expert and may be under a false impression

 

[psneeld]

The real engine guys might have a better answer.....

But I think getting to high revs is more the issue than throttle position. The engine isn't under load and if the parts are coated with oil, theoretically protected.

So if you pull the engine back to high idle before you get past 1/2 your rpm range, not sure if much damage is occuring.

I don't use WOT, if trouble starting at high idle position, I might go up to half throttle....as I have never had problems starting there or less.

 

[menzies]

From the manual.

KEY SWITCH
Turning the key clockwise to the first position will switch on the current. continue turning the key clockwise to start the engine. When the engine starts, immediately turn the key back to the first position while the engine is running.

The key must be kept in the on or first position while the engine is running.
Turn the key counterclockwise as far as possible to stop the engine

STOP BUTTON
Stops engine immediately

However when I turn the key fully counterclockwise the engine keeps running so I always have to use the kill button to turn it off.

I will go down to the boat later and have a look at the Alt/Starter/battery wiring, though I suspect I won't be able to work it out versus the panel. The mechanic, who is a local diesel engine guru (maintains and rebuilds the St John's Pilot Boat engines) will be on board for a sea trial next week so I can ask him.

 

[menzies]

Do what the OP manual says.

Warning Thread Drift.

PS out of curiosity, I looked at what mine (Perkins 6.354) said for starting. It says to advance the throttle to MAXIMUM then start the engine, then bring it down to idle.
I advance it a little, but never WOT. Always starts right up.
Anybody else starting at WOT? Am I actually hurting my engine by trying to be gentle with it?

Are you sure that they meant after you start. My manual says the following, so I would double check that.

Starting
1. Put the gear control in the neutral position.
2. Move the throttle control to the full speed position and return back to idle.
3. Turn the key switch to the first position. Check the voltage meter to see the condition of the batteries. For starting, the voltmeter should not read below 12 volts (24 volts for 24 volt systems).
4. Turn the key to the starting position and as soon as the engine starts, release the key. Move the throttle up until the engine is running at approximately 1000 RPM.
5. Do not crank the starter for more than 15 seconds consecutively. If the engine fails to start with the first attempt, be sure that the starter has stopped completely before re-engaging

 

[rwidman]

When we turn off our Luggers we first turn off the ignition switch and then push the engine kill button. ............

A diesel engine has no "ignition" switch.

On my engine (Volvo) there is a rotary key switch. Turn it one click to the right and the gauges activate. Turn it one more click to the right (spring loaded) and the starter engages. Turn it to the left past the original position (again, spring loaded) and it stops. If you don't turn it back past the original position, the engine continues to run but the gauges don't operate.

Not an "ignition" switch.

 

[psneeld]

Is it only the Alt output that is a concern re shutting off while running?
I thought there is also a concern for breaking the external sensing / excite wire to the Alt also?
However... I'll admit I'm no electron expert and may be under a false impression

Neither am I so I hope someone will step up...but no, I haven't heard that as an issue.

Many newer Alts are self exciting, definitely the single wire ones.

If you have a smart regulator, I would read all the fine print there. It may have guidance.

Yet again, depending on the wiring bundle and aftermarket stuff....who knows?

 

[menzies]

A diesel engine has no "ignition" switch.

On my engine (Volvo) there is a rotary key switch. Turn it one click to the right and the gauges activate. Turn it one more click to the right (spring loaded) and the starter engages. Turn it to the left past the original position (again, spring loaded) and it stops. If you don't turn it back past the original position, the engine continues to run but the gauges don't operate.

Not an "ignition" switch.

So you don't ignite the starter?

 

[psneeld]

From the manual.

KEY SWITCH
Turning the key clockwise to the first position will switch on the current. continue turning the key clockwise to start the engine. When the engine starts, immediately turn the key back to the first position while the engine is running.

The key must be kept in the on or first position while the engine is running.
Turn the key counterclockwise as far as possible to stop the engine

STOP BUTTON
Stops engine immediately

However when I turn the key fully counterclockwise the engine keeps running so I always have to use the kill button to turn it off.

I will go down to the boat later and have a look at the Alt/Starter/battery wiring, though I suspect I won't be able to work it out versus the panel. The mechanic, who is a local diesel engine guru (maintains and rebuilds the St John's Pilot Boat engines) will be on board for a sea trial next week so I can ask him.

Sounds like the setup on many vessels of your size.

Most people hit the kill buttons to stop, then turn the keys off when sure the engines have quit. Usually in 10 seconds or less you can tell they are off.

Your mechs might have a reason....but many mechs I know live in the same urban myth world we do.

If still worried, get a better explanation as to why.....

My total guess is it is better to have the whole start circuit energized for short periods before the engine starts and after it stops rather than engine first and last.

But that fits most engines I have dealt with, not necessarily all.

 

[Ski in NC]

Most boats it does not matter. Most alternators do not care if field is energized on coastdown. Stop it any way you like.

I wired my personal boat engine a little differently. I don't really like start and stop buttons. They require additional motions to get the action desired. Sounds minor, but if you get a stall, it is nice to roll starter quickly.

So I wired mine up with a key switch like a car. Off-On-Start. Only one motion of the hand needed to start or stop. Want to avoid anyone starting engine, key in pocket. Did the same with gennie.

Wired alt so regulator is energized by an oil pressure switch. I think a bunch of Lehmans are similar.

 

[johnrupp]

The Alt would be my concern as well. Wouldn't cutting ignition switch cut 12v sensing and the Alt districts...Similar to turning off the batty SW when running...

No, when turning the battery switch off the alternator field is still energized. The alternator is still trying to produce electric with no place for it to go.

On many boats the key switch energizes the field current in the alternator when it is in the on position. When the key is turned to off the alternator stops producing power weather the engine is running or not.

As mentioned in another post other boats are set up where the field current is controlled by an oil pressure switch and the position of the key switch has no bearing.

 

[TONTOROSS]

I am with Fog, I kill the engine with the kill switch and then turn off the ignition.

What these folks are saying. I do the same thing with Deere, Masey, and International tractors on our place. More than one Mechanics has told me this is the recommended way to shut off a diesel.

 

[dhays]

So I wired mine up with a key switch like a car. Off-On-Start. Only one motion of the hand needed to start or stop. Want to avoid anyone starting engine, key in pocket. Did the same with gennie.

I am interested in this. Did you eliminate the kill switch as well or just the start switch?

It would be nice to get rid of the start button but I would still want the kill switch.

Sad to say, but I occasionally will push the wrong button. Not a problem if I hit the kill switch when the engine is off, but not good if I hit the start button while the engine is running.

 

[Bacchus]

No, when turning the battery switch off the alternator field is still energized. The alternator is still trying to produce electric with no place for it to go.

On many boats the key switch energizes the field current in the alternator when it is in the on position. When the key is turned to off the alternator stops producing power weather the engine is running or not.

As mentioned in another post other boats are set up where the field current is controlled by an oil pressure switch and the position of the key switch has no bearing.

That makes sense...Thanks for clarifing

 

[High Wire]

Are you sure that they meant after you start. My manual says the following, so I would double check that.

Starting
1. Put the gear control in the neutral position.
2. Move the throttle control to the full speed position and return back to idle.
3. Turn the key switch to the first position. Check the voltage meter to see the condition of the batteries. For starting, the voltmeter should not read below 12 volts (24 volts for 24 volt systems).
4. Turn the key to the starting position and as soon as the engine starts, release the key. Move the throttle up until the engine is running at approximately 1000 RPM.
5. Do not crank the starter for more than 15 seconds consecutively. If the engine fails to start with the first attempt, be sure that the starter has stopped completely before re-engaging

Nope, here it is verbatim:
Starting the engine.
Engine controls and instruments will vary according to each individual boat builders preference but, in general, the following instructions are applicable to all Perkins marine engines installed in boats manufactured in North America.
1. Place the gearbox in neutral position. (Borg Warner transmissions have neutral safety switches... (snip))
2. Place the engine speed control at the maximum *speed position.
3. Press the start button or turn the key in the clockwise direction - release as soon as the engine starts. If the engine fails to run, ensure that the starter pinion and engine have stopped rotating before re-engaging the starter motor. Otherwise the flywheel ring and starter pinion could be damaged.
4. Place the engine speed control at the position of desired engine rpm.

* For TV8.510 (M) engines, place the engine speed control at one-quarter (1/4) of maximum speed if the engine or weather is warm or at the maximum speed position, if cold.

 

[Ski in NC]

I am interested in this. Did you eliminate the kill switch as well or just the start switch?

It would be nice to get rid of the start button but I would still want the kill switch.

Sad to say, but I occasionally will push the wrong button. Not a problem if I hit the kill switch when the engine is off, but not good if I hit the start button while the engine is running.

On my Cummins, the fuel solenoid is energize to run, so when you turn the key off it stops.

This runs counter to my preference in that if I lose all electric, the engine will shut down. But I am ok with it as if I start losing voltage it is easy to put a zip tie on the solenoid. Should have plenty of time to do that.

If you have two helms, the key gets complicated. In those cases, start and stop buttons can be more practical.

I have two helms, but upper is primitive with no start/stop. Not real happy about that, may modify it. I rarely run from up there.

 

[kchace]

The key switch for my Lehmans only energizes the engine instruments and the circuits for the Start/Stop buttons. Since they're completely mechanical and no "run" solenoid, no power is required for running. If I shut the key switch off I can't stop the engines with the stop button (which goes to the stop solenoid).

Alternator fields are engergized by an oil pressure switch.

BTW - my Lehman manual says to use 1/4 throttle but I have seen some versions of the Lehman manual that said to use full throttle. I have a problem with high RPM before oil pressure is established. I don't use any throttle and the engines always start instantly.

Ken

 

[markpierce]

Not sure what engine manufacturers mean by terms such as "half" throttle. JD says to start my 4045, set throttle to one third. Does that mean moving the throttle handle one-third of the way between upper and lower limits? If one-third meant to run at one-third of maximum RPM, that would be idle speed. (750 RPM). Regardless, I set the throttle for cold-start starting to result in 1100-1200 RPM (is that half-throttle?), and turn throttle setting to idle once the engine settles.

 

[Ski in NC]

I start LOTS of marine diesels. Always check throttle at dead idle prior to cranking. Only mess with throttle when very cold or airbound or otherwise being hard starting.

 

[koliver]

I start LOTS of marine diesels. Always check throttle at dead idle prior to cranking. Only mess with throttle when very cold or airbound or otherwise being hard starting.

 

[menzies]

I start LOTS of marine diesels. Always check throttle at dead idle prior to cranking. Only mess with throttle when very cold or airbound or otherwise being hard starting.

Interesting comment on being airbound.

I have a manual fuel prime pump on my Luggers, are there people here who do not have a way of clearing out trapped air other than cranking?

 

[psneeld]

Some motors self bleed. My Cat 3208s did and my Westerbeke genset does.

 

[menzies]

Some motors self bleed. My Cat 3208s did and my Westerbeke genset does.

Self bleed by letting them sit for a while if you get air in there from a filter change or running out fuel - or self bleed through cranking?

 

[cafesport]

We have electronic Luggers with electronic twin disk transmissions. Our key switch energizes four control stations as well as our electronic transmissions. Key off, engine off, transmissions off,and no stations are active. Key on, transmissions on, and all stations start stop buttons are active. Transmission has a neutral safety switch and can't start in gear regardless of which station is used to start. Pilot house has the only keys and no shut down switches. Other stations all have start and stop buttons. Lots of variables depending on specific equipment and owners desires.

 

[dhays]

Interesting comment on being airbound.



I have a manual fuel prime pump on my Luggers, are there people here who do not have a way of clearing out trapped air other than cranking?

My Cummins pressurizes the fuel line when the key is turned on. iIRC, Cummins says turning the key on for 30s, turning the key off, then repeating a few times to pump fuel through the filters after a change.

 

[stone beach]

With a simple mechanical governor & the speed control lever in tick over position before cranking the fuel pump is already in the max fuel delivery condition....because the engine speed is below the demand speed....so touching the speed control lever while cranking doesn't do anything.

 

[BruceK]

My Onan MDKD self bleeds. After changing fuel filters I opened what I hoped was the bleed screw,hit the starter, fuel came out and the engine started. Closed the bleed screw, cleaned up, job done.

 

[stone beach]

If you opened a vent that isnt "self bleeding" !!

 

[FF]

"Is it only the Alt output that is a concern re shutting off while running?
I thought there is also a concern for breaking the external sensing / excite wire to the Alt also?"

A proper rotary switch is break before break to kill the field before disconnecting the batt.

Turning off the field is the correct method of turning off an operating alt.

The auto style "one Wire" alt does not have this option .

A second reason to install a remote 3 -4 stage V regulator which is superior for charging house batts