Yanmar 2gm20f

[Ilijanik]

Hi everybody, I am a new sail boat owner. Just got Pearson 30 and I have problem with my yanmar 2gm20f engine. To make it easier to explain shortly, this is the list what I did and the probles:
I did:
Change the oil and oil filter. Now the oil level is 1/3 above minimum
Replaced old fuel with fresh diesel and replaced the fuel filter.
Put new battery
Air bleed the fuel system

What's happening:
The engine, hardly, but starts on key
Once starts, the engine runs on max rpm's with 0 throtle. The only way to stop the engine was to chock the air intake because the fuel shot off ( tried manually on the engine block) does not react.
Checked fuel delivery to the injectors and the fuel after high pressure pump is coming only to
the second injector, closer to the gear box, bot not to the first injector.
On the first start black smoke came from the exhaust, but after that no smoke or steam was coming out on max 3200 rpm's The sea water pump looks like is working good.
Any idea where I can start from? This is my first sail boat and first diesel engine to deal with. Thanks a lot!!!

 

[Cmp1110]

Re check engine oil sometimes a diesel can scavenge oil from crankcase and run on it

 

[Warren Milberg]

The first things I would check are are the throttle and fuel cut-off linkages, both of which terminate on the starboard side of the engine just below the secondary fuel filter. Have someone in the cockpit move the throttle lever while you watch what it's doing at the engine end. Same thing with the fuel-cutoff linkage. Both may need lubrication or replacement. Second thing to check are all the electrical connectors (of which there are many on this engine). Open and clean all of them to make sure the right amount of volts/amps are getting to the starter/solenoid. I can't imagine how your engine could produce 3200 rpms with only one injector working. Make sure your two decompression levers on the top of the engine are in the closed position. You may have a clogged fuel line or a faulty injector and need to remove and clean the first injector or replace it.

 

[fredr]

Has this engine not run in a long time?
The governor must be working because it is limiting RPM to 3200.
I am with Warren. Check the throttle lever / cable to see if it is stuck to wide open throttle. You may just disconnect the throttle and fuel shutoff cable / linkage at the engine and have someone start the engine while you control the levers at the engine.
CAREFUL! Watch that nothing gets caught in the raw water pump belt!
The engine fuel shutoff lever next to the throttle lever should shut the engine down.

If absolutely NOTHING is coming out of #1 fuel line @ the nozzle, no foam / no fuel...
it sounds like the delivery valve in the high pressure pump is stuck open, so fuel is moving up into the line toward the injector nozzle, then returning into the pump when the plunger moves down. The delivery valve lets fuel into the line and shuts, trapping the fuel so the fuel can not return into the pump, fuel pressure then over comes spring pressure in the nozzle, and injects into the cylinder.
Remove the fuel line at both ends.
Remove the fitting in the pump that the line connects to.
BE CAREFUL! There is a spring, "O" ring / washer, and a delivery valve. I believe this valve is not seating / sealing.

 

[Ilijanik]

First, thanks guys for the replys on my problem.
I did loose the fuel connector before second injector and the engine stopped, which for me looks like is not running on lube oil. Then I removed the fuel tube (blowed, not clouged) from high pressure pump to the 1st injector and cranked the motor. Engine started and no fuel was caming out straight from the pump. Did not see any washers or springs there. While testing, all operations were done on the engine by itself, not from the helm puling control cables.

 

[s sauer]

Diesel Engine repair

No disrespect intended, but if this is you first experience working on a diesel, you may be time and $$$ahead to get a professional mechanic involved.
Working on a high pressure pump is beyond most novice mechanics ability and can easily result in very expensive repair costs. At the least, if you feel competent to trouble shoot the low pressure side, I'd suggest you get a SELOC Chilton Marine Manual for that engine.

 

[Ilijanik]

Having fuel coming to the second injector means I did good air bleed on the low pressure fuel side or is there more to do?? Any connections between fuel not coming to the first injector and throttle and shutoff not reacting?

 

[fredr]

Yes, the fuel system is bled out.
S Saur's point is well taken. If you are over your head, get help.
First of all, regardless of who will perform the work, you should get a service manual for the 2GM. It is a great manual that will be very valuable.

If you have #2 injector line delivering fuel then both should be delivering fuel.

If the throttle rack in the pump is positioned to let #2 get fuel, then #1 should also be getting fuel, unless the injection pump plunger for #1 is stuck because of old fuel.
If you have not resolved the throttle and engine stop issue, and the throttle and engine stop will not move freely, then the injection pump may not be operating because of old fuel that has turned to varnish and will not let the rack or the #1 injection plunger move freely.
So yes, there can be a connection to the 2 issues.
At this point, I would find a mechanic to make these repairs.

If you insist on checking further.
The delivery valve is UNDER the fitting that the fuel line connects to on the injection pump.
Remove the fuel line from BOTH ends.
Remove the fitting on the injection pump that the #1 line screwed on to.
There you will see a spring and delivery valve.
Under the delivery valve is the injector pump plunger.
Now turn the engine and see if fuel is coming out.
If not, and you see no up / down movement of the plunger, you can try and pour WD40 or PB blaster in there and let it soak for several days to free up the parts.

At this point, you should get a mechanic with knowledge of Yanmar fuel system to have the injection pump examined / removed / rebuilt.
Removing the injection pump is not hard, but installation is !
To install the injection pump you must get the pump control rack into the governor lever slot.
IF YOU GET THIS WRONG, THE ENGINE CAN REV UP UNTIL IT GOES BOOM!
So I think you have done all you can do at this point.
I would find a mechanic to make these repairs.

 

[Ilijanik]

Thank you to all. Now, definitely I am getting a diesel mechanic to help me out.