Yanmar 3qm30 NO START ISSUES

[Chayal]

Hi all,

I’m hoping to receive some input regarding a no start yanmar 3qm30.

Backstory: engine sat without diesel by previous owner for 3 years until I took
ownership.

I cannot get any fuel from the suction side through the injection pump.
Currently, I am running clear hose into a jerry can, with a prefilter and a 12v
Pump (facet) Hooked directly to the injection pump. The pump has been carefully
Bled out, and no air appears to be traveling through the lines. I have repeated this step many times.

I’m cranking the engine over, decompressed, obviously raw water intake closed, both by hand and by starter. ~10 seconds.

There is nothing coming out of the high pressure lines.

I’m suspecting the injection pump internally frozen somehow from sitting?
I’ve tissue paper tested under the pump and it seems to be holding its prime well with no leaks.

Any insight would be great before I remove the pump and send it out for testing.

Am I missing anything?

[Chayal]

I forgot to add... throttle is fully open when trying to bleed the high pressure lines!

[Chayal]

I’ve tried spinning the engine both by handcrank as well as starter motor (decompressed) at least 4-5 minutes total with high pressure injector lines cracked. 15 seconds then a break for starter. I’ve tried one at a time as well as all 3 cracked open. Cracked at the injector.

I’ve also had these lines completely removed and blew through them to make sure no instructions were in the lines.

[Wotname]

Originally Posted by Chayal

Hi all,

I’m hoping to receive some input regarding a no start yanmar 3qm30.

Backstory: engine sat without diesel by previous owner for 3 years until I took
ownership.

I cannot get any fuel from the suction side through the injection pump.
Currently, I am running clear hose into a jerry can, with a prefilter and a 12v
Pump (facet) Hooked directly to the injection pump. The pump has been carefully
Bled out, and no air appears to be traveling through the lines. I have repeated this step many times.

I’m cranking the engine over, decompressed, obviously raw water intake closed, both by hand and by starter. ~10 seconds.

There is nothing coming out of the high pressure lines.

I’m suspecting the injection pump internally frozen somehow from sitting?
I’ve tissue paper tested under the pump and it seems to be holding its prime well with no leaks.

Any insight would be great before I remove the pump and send it out for testing.

Am I missing anything?

I would be surprised if all three pumps in the injection pump failed due to the engine sitting idle for three years.

Your bleeding method sounds fine.

The injector lines (pipes) on the 3QM30 are quite long (almost 3') so I am wondering if you are turning the engine over long enough to bleed them.

You could try the bush method of bleeding if you are feeling lucky.

Put some diesel into a small spray bottle (say a pint or half litre size), set the nozzle to mist and gently spray diesel mist into the air cleaner while cranking. If the rest of the engine is OK, it will fire and run roughly. You keep it running by judicious squeezes of the spray bottle. It will shake around and be rough as the timing is non existent etc. However it will be working the injection pump and if it starts running smoothly, you know the lines are bleed. You might need to keep it running this way for a minute or so.

Good luck and let us know what happens.

[Chayal]

Thanks for the reply and insight Wotname. I was hoping you would see this thread.

I was able to get the engine to run roughly with the combination of a tiny spray bottle and a soaked rag held near the air Intake. It’s very tough to keep her idling, but I was able to hear the engine running which was a relief.

After a few of those sessions, I went to check the high pressure lines. I figured I would at least hear some air escape or hiss, but nothing. Not even a dribble of fuel!

I’m a bit worried the previous owner wasn’t honest with this engine.

There appears to be tool marks on the 4 injection pump nuts, it looks like someone may have been in this engine already...

I removed the block off plate to see if I can find anything abnormal. The lever moves nicely, and the regulator spring is attached.

Just looking at the parts diagrams, there is another fuel control lever. I’m suspicious if this is hooked up correctly?

It’s tight in that space and I’m using a mirror and flashlight.

[Chayal]

The way I’ve bled the low pressure side is with a 12v pump and cracking the injection pump bleed. There’s steady fuel now for sure. Throttle closed.

I’m wondering if it’s just more air buildup in that pump that is being stubborn, perhaps an airlock in the fuel delivery assemblies?

Nothing is going to feel more satisfying Then saving this engine and have it come to life. This thing is a pleasure to work on

[Chayal]

When the throttle is closed the regulator spring has a ton of free play ^

[Chayal]

Ok just an update.

I ended up pulling the pump. The back of it is soaked in diesel! Also, the plunger/slider on the pump is not able to move.

Wotname, I think there is a possibility this thing might have sat for longer then the 3 years I was told.... this is the original motor and the hours panel shows 590 hours.

[Wotname]

Do you have the 3QM30 service manual or only a parts manual?

[jimbunyard]

If the rack is stuck in the 'no fuel' position, no fuel will be delivered to the injectors. If you're mechanically inclined and patient, you can dissassemble and clean the pump yourself, and if nothing is corroded, it might actually work as it is. There is a detailed description of how to do this in this manual.

http://www.hunter37.com/Yanmar_3qm30.pdf

You could try it, and if unsuccessful, or partially successful, there's always the injection pump shop...

[Compass790]

Originally Posted by Chayal

Ok just an update.

I ended up pulling the pump. The back of it is soaked in diesel! Also, the plunger/slider on the pump is not able to move.

Wotname, I think there is a possibility this thing might have sat for longer then the 3 years I was told.... this is the original motor and the hours panel shows 590 hours.

If the back of it is soaked in diesel you have to dismantle pump & check it as there should be no way for diesel to get there. Obviously the seized plunger ( s) is an issue as well.
I'd have a go as Jim Bunyard suggests as long as you are competent mechanically. It would cost a lot for a new one but plunger/barrels & delivery valves are a lot cheaper.
Take pics & be clean as possible

[a64pilot]

I would pull it, and the injectors and have it professionally done. There are settings and adjustments and checks that you cannot due to a lack of proper equipment.
I’d also check to make sure none of the lines have any rust internally.
Yes it’s likely that you can take it apart and make it work, but there is little chance that it will be correct.
I can adjust valves without a feeler gauge too, or time ignition by ear, and the engine will run, but it won’t be correct, close maybe, but not right.

If your after an engine that is trouble free, runs well, doesn’t smoke and doesn’t break down, have the injection parts done, that’s why injection shops exist, this isn’t a brake job on your car.
Your part will be ensuring you get it timed as perfectly as possible when you put it back in, don’t time by ear or just put it back to existing marks etc.

A good shop will most likely show you what is done if you ask, once you see the testing and subsequent adjustments, you’ll understand why you can’t do it correctly.

When I bought my boat 6 years ago it was 27 years old and had 500ish hours on the engine, it still purrs like a kitten and doesn’t burn oil and has about another 1,000 hours on it.

[Chayal]

I do have a copy of the service manual ^ thanks.

I have it on the bench now... I’ve loaded it topside with mmo
Hoping it may loosen up.

I still have high suspicion someone has already been in this pump.
Someone added the scribe marks as mentioned in the service manual on the pump already.
Not to mention all the tool marks on the bolts/nuts on the pump.

I’m gonna leave it in the soak for a bit and see if she will come loose.
Ideally I’d like to send this pump to the shop with a sliding functioning fuel rack for calibration, but one thing at a time.

The previous owner had the injectors rebuild, and did provide me with an invoice.
I have a feeling this thing sat for a long time. With no fuel.

I appreciate everyone’s input.

[Compass790]

Yes well if they have botched the reassembly you will have to get it put on a pump tester but yes definitely try the soak first.It's critical to keep each part to each cylinder pump matched.
If it's rusty inside the delivery valves or plunger & barrels it will have to be rebuilt but I wouldnt panic about the 3 years IF it hasnt had water sitting in it.
However given the fact that you see evidence of leaking diesel & seized plunger it doesnt bode well. If the previous owner botched the assembly he could have caused the plunger & barrel to seize. Basically the plunger & barrel diesel seal depends on its lap fit & the copper crush washers.
.
Good luck with the soaking & please post back what you find out in the end

[paralog]

Originally Posted by jimbunyard

If the rack is stuck in the 'no fuel' position, no fuel will be delivered to the injectors. If you're mechanically inclined and patient, you can dissassemble and clean the pump yourself, and if nothing is corroded, it might actually work as it is. There is a detailed description of how to do this in this manual.

http://www.hunter37.com/Yanmar_3qm30.pdf

You could try it, and if unsuccessful, or partially successful, there's always the injection pump shop...

taking an injection pump apart and trying to clean it is not really for the do it yourselfer. The tolerances and settings are so fine you can easily screw it up. Best to take it to a diesel shop and let them do if for a couple hundred bucks. And yes I have rebuilt pumps and injectors in a proper diesel shop.