Diesel Problems

[Nodak7]

My good friend and diesel expert died last week and now I need him so I turn to you guys for help.

Today we had no wind so we ended up motoring for 4 hours to get back to the Marina. After we got into the slip I went to shut down the engine and it would not shutdown! I tried everything I could think of but she just would not respond. I reved it up and pressed the stop button and the engine sputtered and I thought it would shutdown but it would act like it was but just keep "dieseling" and sputtering. Finally it did totally stop. Anyway I never got any alarms so I don't think it was hot but ??? I am thinking the water pump might not be pumping but I did not want to start it to see. I checked the inlet strainer and it was clear. Does anyone have a suggestion?

 

[Johnb]

I had intermittant episodes of loss of power that eventually went away after I changed out the cam shaft driven fuel pump on my 3 QM (1983). Its the small one on the starboard side low down and toward the bow end of the engine - the one you pump by hand to bleed the system.

This is not a very expensive item and pretty easy to do. I don't recall if a new gasket came with the pump but I figure you should have one on hand if you decide to do it.

 

[Nodak7]

I had intermittant episodes of loss of power that eventually went away after I changed out the cam shaft driven fuel pump on my 3 QM (1983). Its the small one on the starboard side low down and toward the bow end of the engine - the one you pump by hand to bleed the system.

This is not a very expensive item and pretty easy to do. I don't recall if a new gasket came with the pump but I figure you should have one on hand if you decide to do it.

Thanks John. But if it were not getting fuel the motor would try to stop..correct? In this case it does not want to stop. I am no getting the connection?

 

[Steve Dion]

I would check the fuel shut off adjustment. Not sure what engine you have . Some have a manual cable and others have a solenoid shut off, so I would start there. You can usually put a large wrag over the air i take to shut her down too.

 

[Nodak7]

I would check the fuel shut off adjustment. Not sure what engine you have . Some have a manual cable and others have a solenoid shut off, so I would start there. You can usually put a large wrag over the air i take to shut her down too.

Thanks Steve. It must be a solenoid because I have no cable. How do I go about checking this?

 

[SEMPERAVANTI41]

Hi Nodak7; You need to check the operation of the "Engine Stop Solenoid" .It is on the port side of the engine viewed from in front of the engine. The plunger should extend when the engine switch is in the on position, and retract when you press the stop button with the key switch in the on position. On the back of the engine you will find a sheet metal bracket with relays attached. The relay with the white/brown wire attached to it is the control relay for the stop solenoid. Check if you can feel or hear a click when either the engine switch is turned on, or when the stop button is pressed. This test will tell you if the control circuit is good. After this you can follow the red/black wires to the stop solenoid and visually check its operation. If you need the shop manual let me know!

Regards;

Semper

 

[Nodak7]

Hi Nodak7; You need to check the operation of the "Engine Stop Solenoid" .It is on the port side of the engine viewed from in front of the engine. The plunger should extend when the engine switch is in the on position, and retract when you press the stop button with the key switch in the on position. On the back of the engine you will find a sheet metal bracket with relays attached. The relay with the white/brown wire attached to it is the control relay for the stop solenoid. Check if you can feel or hear a click when either the engine switch is turned on, or when the stop button is pressed. This test will tell you if the control circuit is good. After this you can follow the red/black wires to the stop solenoid and visually check its operation. If you need the shop manual let me know!

Regards;

Semper

Excellent suggestion Semper. I was just doing a search on the net to see where the fuel shut off switch was located. After you described it I remember looking right at it. Can it be manually pressed to shut down the engine? The next time I am up at the boat I will do that check. I was thinking about it and thought that since we had been cruising for a number of hours before I shut it down that maybe she had built up some carbon but I don't believe it would have continued to run if the fuel had been shutdown so I was working that angle. It sounds like an easy check and probably the problem. Hopefully they are not difficult to changeout if that is the problem. The engine only has 371 hrs on it.

I guess the only good way to shut it down with a bad solenoid is to close the fuel valve at the tank but that could take some time to run it down.

 

[SEMPERAVANTI41]

There is an emergency stop button at the end of the stop solenoid which would be the preferred method for stopping the engine. If you turn off the fuel supply, you might hurt the injection pump as it is lubricated by diesel.

 

[Nodak7]

Yeah, been there and done that! Changng the fuel filter, got distracted and forgot to open the fuel tank valve. Amazing how long the engine can run without that open! Thank goodness it quit when we were just about out of the Marina and could put up the sails to manuever.

 

[Nodak7]

Got a chance to go back to the boat and check on that shutdown solenoid. It did function properly. I started the engine and shut it down with no problem. I even tried the emergency shutdown just to make sure it work. It did! Started it up and ran it until it was warm and then shut it down with no problems. Have to like those self healing problems. Thanks for the help.

 

[heritage]

Solenoid problems tend to be intermittent and there is a real good chance that it will happen again. The copper contacts in the solenoid develop burn spots caused by electrical arcing. If or when it happens again, best to replace the solenoid or just shut down manually.