Yanmar Stalled

[Wakadui]

Do some diesel engines need electricity to remain running?

Have a 4JH4-HTE 110hp Yanmar. Having battery bank issues (I know... shouldn't be sailing, but a clear day in Feb with 20kts of wind and 60 degrees!... just couldn't let that one go by). Didn't know how bad the bank was until engine battery alarm triggered under idle power. Engine died soon thereafter (under idle power). Eventually got engine started and immediately placed it into gear and increased RPM's to 2,000 to get more amps out of alternator. Luckily, motored safely to slip.

Will save battery bank issues for another discussion, but would like some help with why a diesel engine would die when running.

My Beneteau has an engine compartment blower that remains on as long as the engine is running. I speculate that if the blower has no juice (voltage) to run then engine shuts down for safety sake. Could this be the reason for the engine shut down under idle power?

[Chief Engineer]

Some need electricity to hold a stop solenoid open to keep it from shutting down.

When you press the shutdown button....you are releasing the solenoid...the action then stops the engine.

I have seen these on Perkins Diesels and others.

[delmarrey]

A Yanmar doesn't need power to run once it's started but does need power to shut it down from the panel. It can be shut down manually by turning the stop lever at the fuel injection pump CW and hold until motor stops.

How long had the motor been running?

[Wakadui]

Engine had been running for 10 mins in idle mode before stalling. Engine battery alarm sounded 8 minutes into it.

[ViribusUnitis]

If you don't have a lever to "kill" the engine that is diffrent from the key, it requires power to keep a solenoid activated to keep the engine going. Without power to keep the solenoid in the on possiton, it defaults to off, killing the engine. Such a unit can be on any engine, as it simply replaces the kill lever with a bit of cheap electronics. However, if it's just the solenoid drawing power, the engine can run for a VERY long time. The unit doesn't draw much juice at all.

To me it sounds like you have a bad alt. The low battery alarm shouldn't have come on with the engine running if the alt. was charging. If you have an alt. with a shorted diode, the alt. can actualy drain power from the battery all the time that you have the key on. This would prevent it from actualy charging anything, and quickly drop the voltage so the low bat. alarm came on.

It sounds to me like your bad alt. has a set of shorted diodes. While the key is in the "on" possiton it's drawing power from the battery, rapidly killing the battery. When the voltage from the battery got low enough, the solenoid killed the engine.

Thus if it was me, I'd take a look at your alt. first.

[sigmasailor]

Maybe the alternator was not energized yet. Some (most) alternators do not work at idle. Engined need to be revved to 1000 or even 1500 rpm to get them going. If you have a bad battery maybe the voltage dropped just below the point where the solonoid quit. I just wonder how you managed to restart it after it had died. Anyway after that you woke up the alternator by revving your engine and came home safely.

[Zanshin]

What about the fuel pump - I would think that even before the shutoff solenoid turns off, if the fuel pressure pump(s) don't have sufficient electrical energy then the pressure into the common rail would drop and cause fuel starvation.

[Hud3]

Del's right.

The Yanmar 4JH3BE in my former Island Packet 380 will run until the fuel is gone with no battery power whatsoever. It has a Stop button in the instrument panel, which needs 12 DC to stop the engine. With no power available, it doesn't function.

Something other than lack of power is causing your engine to conk out. Try checking out the fuel path, starting with the filter.

[Charlie]

Originally Posted by delmarrey

A Yanmar doesn't need power to run once it's started but does need power to shut it down from the panel. It can be shut down manually by turning the stop lever at the fuel injection pump CW and hold until motor stops.

How long had the motor been running?

Originally Posted by Hud3

Del's right.

The Yanmar 4JH3BE in my former Island Packet 380 will run until the fuel is gone with no battery power whatsoever. It has a Stop button in the instrument panel, which needs 12 DC to stop the engine. With no power available, it doesn't function.

Something other than lack of power is causing your engine to conk out. Try checking out the fuel path, starting with the filter.

when I have someone new on the boat I sometimes tease them by asking them to turn off the engine (Yanmar 4JH4E) When you turn off the key you can't turn the engine off from the stop switch. You have to either turn the key off or go down below and press the kill lever.

[daddle]

Some installations will stall if the electric fuel lift pump
fails. Especially if the hoses are long, filters iffy or fittngs a bit leaky.

[Charlie]

Originally Posted by daddle

Some installations will stall if the electric fuel lift pump
fails. Especially if the hoses are long, filters iffy or fittngs a bit leaky.

Don't know about the 4JH4- HTE but the 4JH4E does not have an electric fuel pump. It is a mechanical pump that runs off of the engine not a belt.

[BornSailor2]

I agree with Hud3 the engine does not need electric to run - Some do have electric to glow coils for starting. Check Water Fuel (Mechanical Pump) Oil.

[delmarrey]

I think I would check your idle RPM rate. It may need to come up a bit. Also check your fuel filter, it may be starving the motor just a little.

If it were your batteries, you would not have been able to restart it again.

BTW- 4JH4-HTE do not have glow plugs but uses an air heater.

My old VW diesel had the electric activated solenoid, if I lost power - I lost my motor. Not a good situation if one is trying to put out a fire or running bilge pumps with ones motor/power.