What a Buzz-Kill ! Yanmar Mechanic Says . . .

[delmarrey]

I believe the 3JH and the 4JH have the same design.
If so, then by pushing on the back of the solenoid should shut down the motor.
I hope your not confusing the throttle lever with shut down solenoid.

.

[Sailor Vee]

This is a 4JH-3 HTE which has an integral solenoid instead of the surface mounted type shown in this detail. The wire comes in directly at the center...the manual shut off is much the same however. There is nowhere to push on the solenoid to activate it. It may well be that it activates the exact same mechanism which was your original point.
The mechanic said that eventually my manual would stop working too but it seems VERY positive in its action. It may well end up being too low of a voltage due to a faulty ground as some have suggested. This is frustrating but I am just rigging a pull cord out through the engine housing and pulling on it when I need to shut her down for now. Thank you so much for your suggestions.

[delmarrey]

Originally Posted by Sailor Vee

This is a 4JH-3 HTE which has an integral solenoid instead of the surface mounted type shown in this detail. The wire comes in directly at the center...the manual shut off is much the same however. There is nowhere to push on the solenoid to activate it. It may well be that it activates the exact same mechanism which was your original point.
The mechanic said that eventually my manual would stop working too but it seems VERY positive in its action. It may well end up being too low of a voltage due to a faulty ground as some have suggested. This is frustrating but I am just rigging a pull cord out through the engine housing and pulling on it when I need to shut her down for now. Thank you so much for your suggestions.

One of the things that erks me. Yanmar is so inconsistent with its designs.

So, you've gone to a mechanical shut down! One thing you may want to do is keep a board in the motor compartment that will cover the intake tube. If the mechanical system fails then you can just block off the airflow to shut it down.

Enjoy the trip!

[Sailor Vee]

I completely agree...The "3" in the number refers to the third version of this engine design. There are several areas I have discovered where my version is completely different from the earlier models (one hopes for good reason...)
e.g. the solenoid insert, the fuel filter, the helm panel I can't find anywhere...
As a comparatively new boat owner with finite mechanical skills it poses problems.
I am holding off on doing anything major until I get a second opinion that indeed there is a history of this happening. The reason I can't believe it is electrical is that I first checked it with my voltmeter-a really good marine electronics guy double checked it as did the diesel mechanic. (Plus The solenoid is activating with what appears to be full range throw.)

[ub1]

try jumping it at the starter. on mine the wire from starter switch to starter was too long and didnt have enough amperage to start, just clicked. fixed it by putting relays on both engines.

[Ken Andersen]

Originally Posted by GordMay

Yanmar Service Bulletin (page 7):

YANMAR STOP CABLES
We would like to bring to your attention that the stop cables are not being lubricated periodically.
The stop cables are a steel cable with a steel jacket. In order to maintain the cable in good working order it is important to grease the cable periodically with a water proof grease.
This is done by loosening the locking screw in the barrel at the engine side of the cable. Pulling the inside cable out at the panel, take a water proof grease and generously coat the cable and shank.
When the cable
is reinserted, make certain the cable is pushed all the way in and the shut down arm is in the complete run position before locking the barrel screw back up.
Failure to lubricate the stop cables will result in:

CAUSE (A) CABLE RUSTED IN SHUT DOWN POSITION
RESULT (B) ENGINE WOULDN'T START

CAUSE (A) CABLE RUSTED IN FULL RUN POSITION
RESULT (B) ENGINE WOULDN'T SHUT DOWN

CAUSE (A) CABLE RUSTED IN PARTIAL RUN POSITION
RESULT (B) ENGINE WILL NOT REACH FULL RPM

CAUSE (A) CABLE RUSTED IN ANY POSITION AND FORCED OUT
RESULT (B) PANEL FACE WILL FRACTURE

If any questions, please contact the service department.

Here ➥ http://ldmarineservice.com/files/yanmar_bulletins.pdf

Good luck.

Thanks Gord,

I do have the stop cable. Several times in the past it's frozen up. In frustration I squirted a little oil on the pull bar and eventually the cable freed itself. I wasn't aware of the service bulletin. Makes a lot of sense to periodically fully grease cable. Thanks for the tip.

Ken

[Auspicious]

Originally Posted by Ken Andersen

I do have the stop cable. Several times in the past it's frozen up. In frustration I squirted a little oil on the pull bar and eventually the cable freed itself. I wasn't aware of the service bulletin. Makes a lot of sense to periodically fully grease cable.

Motorcycle shops will often sell a small clamp-on fitting that allows you to fully lube a cable without pulling the inner wire from the outer sheath. They sell them to use on brake and clutch cables.

Sure glad I didn't get rid of mine when I sold my last motorcycle!

[Sailor Vee]

Originally Posted by ub1

try jumping it at the starter. on mine the wire from starter switch to starter was too long and didnt have enough amperage to start, just clicked. fixed it by putting relays on both engines.

When you say "jumping it" at the starter I assume you mean at the STOP switch... do you mean testing it with a battery jump or to boost the strength with an additional relay? I have a good relay right before the solenoid that tests our as fine.

Sailor Vee

[sky5jump]

I had a small set of yanmar generator motors I converted for our cat. The stupid things needed to have the solenoid energized to open the fuel rack, just opposite any other diesel I have ever owned or worked on. Makes no sense to take a motor that doesn't require electricity to run then put a solenoid that requires to be energized to run. Thanks again Yanmar

[hard aground]

Just for fun have you tried swapping the solenoids between engines to see if your problem switches engines? That would at least take one piece out of the puzzle. Have alos more than once metered a wire that read a ground state while hooked up, but once it was disconnected from said relay/solenoid/whatever it no longer was grounded.

[delmarrey]

Originally Posted by sky5jump

I had a small set of yanmar generator motors I converted for our cat. The stupid things needed to have the solenoid energized to open the fuel rack, just opposite any other diesel I have ever owned or worked on. Makes no sense to take a motor that doesn't require electricity to run then put a solenoid that requires to be energized to run. Thanks again Yanmar

It's so one can at least get to port, if hit by lighting, destroying all electronics. Then the motor can be shut down by manual actuation. Or, if you lose your battery power from a bad alternator.

[Cormorant]

By any chance do you have a schematic of the solenoid circuit? Check to see if there is a thermistor in the circuit. This is a longshot, but I have a tractor with a Yanmar motor, and a little $3 thermistor in the fuel shutoff solenoid circuit went bad. The thermistor controlled the voltage going to the solenoid in the initial few seconds to open it, when you need a fairly high current draw. This malfunction prevented the solenoid from opening, in my case, so the tractor wouldn't start. But in your case perhaps something similar could prevent shut-down. Like I said, a longshot, but maybe worth a look.

[delmarrey]

Originally Posted by Cormorant

By any chance do you have a schematic of the solenoid circuit? Check to see if there is a thermistor in the circuit. This is a longshot, but I have a tractor with a Yanmar motor, and a little $3 thermistor in the fuel shutoff solenoid circuit went bad. The thermistor controlled the voltage going to the solenoid in the initial few seconds to open it, when you need a fairly high current draw. This malfunction prevented the solenoid from opening, in my case, so the tractor wouldn't start. But in your case perhaps something similar could prevent shut-down. Like I said, a longshot, but maybe worth a look.

Here is the download for the manual: http://www.yanmarmarine.com/theme/ya...Manual-ENG.pdf

On page 54 is the schematic, and it does show a couple diodes, one on each side of the stop switch but nothing on the solenoid (may be built in). If one of them diodes is cooked it could drop the amps enough to create a weak solenoid. Just because the solenoid moves doesn't mean it's strong enough to close the valve. Diodes can show continuity w/o actually being functional (cooked).

[JohnT]

Originally Posted by delmarrey

Here is the download for the manual: http://www.yanmarmarine.com/theme/ya...Manual-ENG.pdf

On page 54 is the schematic, and it does show a couple diodes, one on each side of the stop switch but nothing on the solenoid (may be built in). If one of them diodes is cooked it could drop the amps enough to create a weak solenoid. Just because the solenoid moves doesn't mean it's strong enough to close the valve. Diodes can show continuity w/o actually being functional (cooked).

Those schematic "diodes" look more like terminal lug symbols to me! I cannot see a diode in the kill switch circuit at all, other than the ones shown on the secondary panel wiring.
John

[delmarrey]

You could be right!