Yanmar 2qm20 not starting troubleshooting

[thesauvage]

Second problem I've encountered when putting the engine in FWD gear is a massive water leak from the shaft seal

Photo 1: https://i.imgur.com/8kOnWZQ.jpg
Photo 2: https://i.imgur.com/fnkOSzu.jpg

The water intrusion while in gear, is big enough to 'wash your hands' so the amount equals an open water tap.

Photo of where water Intrusion is originated:
https://i.imgur.com/eLArw0s.jpg

If I disengage gear, the intrusion lowers, I turned the shaft manualy back/forth until the shaft was sealed again. (I've to admit my heart fainted a bit though)

Who knows this kind of shaft seal? It is completely made from rubber. What is the small rubber fill nipple for? Grease?
Any advice how to reseal/service this kind of shaft seal?

[Wotname]

Originally Posted by thesauvage

...........

But the Charge alarm keept sounding throughout the whole time. I also noticed that a loud squeeking noise is coming from the alternator, while the ignition key is in start position. On top the engine seems to run less smooth when the key is in ON position. Please see video:

Video 2: https://youtu.be/5MY8UkgeefE


I suspect the alternator is not wired correctly, or damaged/dead? Possible? What do you guys think?

Your suspicions are correct!
If you haven't already done so, download a copy of the 2QM20 service manual from the library section of CF. Read chapter 11, it will help you pinpoint the problem. There is a ton of information in chapter 11. https://www.cruisersforum.com/forums...p?do=file&id=5

As a teaser, here is the basic alarm circuit, it isn't too complex.

[Wotname]

Originally Posted by thesauvage

Second problem I've encountered when putting the engine in FWD gear is a massive water leak from the shaft seal
........

Who knows this kind of shaft seal? It is completely made from rubber. What is the small rubber fill nipple for? Grease?
Any advice how to reseal/service this kind of shaft seal?

It is a dripless shaft seal; there are various manufacturers - google will help you find the exact one you have.

The only way to fix this properly is to replace it - and soon!!!!!!

When it is working properly, no water comes in; when they fail, it can be spectacularly bad.

[Hat]

I believe you’ll need the tool to then clean the injectors. If any fuel has stayed in the system for a long period it almost becomes like a glue. Hope that helps.

[lituya1617]

I completely overhauled a 2GM20F and learned a lot about the engine in the process. Although I am an old aircraft mechanic, this engine is really impressive. The thing that hurts these engines is the water injected into the exhaust. When the engine is shut down, the hot salt water in the muffler evaporates and coats the inside of the cooling engine cylinders and the heads and valves with corrosive dampness. This causes a lot of damage to the metals and can create very poor compression. If this little engine is mechanically sound, you have fuel pressure, and there is no air in the injectors, it will fire and run almost as soon as it turns over, sometimes in less than two revolutions. If you see white smoke from the engine, something is amiss with the compression. This engine has 23:1 compression ratio and fuel will burn if it is injected into a cylinder at such a pressure - a couple thousand pounds per square inch. On the other hand, ether starting fluid will burn at a much lower pressure and that explains why it starts but will not run. I assume the fuel squirting from the injectors when you cracked the fitting means the injectors are getting fuel. Now, remove the injectors and do a compression test. If you carefully bang on the injectors and use a little liquid wrench, they will come out with a small pry bar. No puller needed 99% of the time. If you have low compression, take the head in for a valve job and do a leak down test on the rings. You may find, as I did, that the head has very heavy pitting and the valve seats are so rusted they have to be replaced. I tell you, wet exhausts are a prescription for misery. Get a keel cooler and dry exhaust - no trouble there.

[David Mathis]

A starting problem along with stalling was experienced with my Yanmar diesel generator engine. The problem was finally traced to the fuel solenoid not opening and occasionally closing while running. The problem was not the solenoid, but was the wiring to keep it open. After trying numerous fixes to find the problem, I tied the solenoid open with a piece of twine and it ran like new. More trouble shooting found the source of the problem to be corrosion on a plug. The plug was cleaned, grease was applied to keep the moisture away, and it was reconnected. Problem solved.

[col50]

I can see in your videos that the alternator belt is very loose.

[wallyallweather]

I have a 2qm20 and It sounds like a old fuel issue. If there is a way to get fresh Diesel to the engine after the starter fluid is used that may be the trick.
Is the diesel 4 years old too ? It can absorb moisture over time.

[fxarcher]

Originally Posted by lituya1617

I completely overhauled a 2GM20F and learned a lot about the engine in the process. Although I am an old aircraft mechanic, this engine is really impressive. The thing that hurts these engines is the water injected into the exhaust. When the engine is shut down, the hot salt water in the muffler evaporates and coats the inside of the cooling engine cylinders and the heads and valves with corrosive dampness. This causes a lot of damage to the metals and can create very poor compression. If this little engine is mechanically sound, you have fuel pressure, and there is no air in the injectors, it will fire and run almost as soon as it turns over, sometimes in less than two revolutions. If you see white smoke from the engine, something is amiss with the compression. This engine has 23:1 compression ratio and fuel will burn if it is injected into a cylinder at such a pressure - a couple thousand pounds per square inch. On the other hand, ether starting fluid will burn at a much lower pressure and that explains why it starts but will not run. I assume the fuel squirting from the injectors when you cracked the fitting means the injectors are getting fuel. Now, remove the injectors and do a compression test. If you carefully bang on the injectors and use a little liquid wrench, they will come out with a small pry bar. No puller needed 99% of the time. If you have low compression, take the head in for a valve job and do a leak down test on the rings. You may find, as I did, that the head has very heavy pitting and the valve seats are so rusted they have to be replaced. I tell you, wet exhausts are a prescription for misery. Get a keel cooler and dry exhaust - no trouble there.

I could not agree more! As I read all these posts and watch many videos, it is always the same story. A sea chest for water intake eliminating all those oh so convenient through-hulls, along with a keel cooler and a day tank with too many big fuel filters will eliminate 90% or more of all mechanical problems. Essentially you would want to miniaturize commercial boat systems that will withstand anything and minimize downtime. Look at the Northhavn line of boats. That is how you do it! And yes, even a fiberglass sailboat can be keel cooled.

[Robert Jansen]

Work through the glow plug system. There are any number of minor issues which can prevent the operation of the glow plugs. Start with the fuse. Next in order: the glow plug relay. Third (least likely): the glow plugs themselves. My money is on the relay.

[Americanrancher]

Originally Posted by thesauvage

First of all, Thanks to everybody, that contributed on this thread. Wich really helped me solve my engine problem.

Update:

I was back at the boat today and wanted to rigg the direct fuel feed to the HP pump. It was then, I noticed that I could rotate all fuel lines, despite of the attached hose clamps.

So I decided to inspect ALL fuel lines, before anything else. I went ahead and took off all fittings cleaned them. While re-attaching the hose clamps, I even found one, that was completely broken, so the fuel line was basically just sitting on the connector nipple.
After I was done fiddling all hoses back on again, I throughly bleed the whole fuel system (from primary fuel filter up to the injectors).

I decided to give it one more try, before deviating to a direct fuel feed to the HP pump, and.... IT STARTED!
Without any hassle, starter spray or decompression lever use. It cranks for about 1 second and fires right up.

Video 1: https://youtu.be/1e8Os7KF9NE

But the Charge alarm keept sounding throughout the whole time. I also noticed that a loud squeeking noise is coming from the alternator, while the ignition key is in start position. On top the engine seems to run less smooth when the key is in ON position. Please see video:

Video 2: https://youtu.be/5MY8UkgeefE


I suspect the alternator is not wired correctly, or damaged/dead? Possible? What do you guys think?

There are THREE reasons that a diesel engine will not run: 1 FUEL, 2 FUEL,
3 FUEL.

[Americanrancher]

Originally Posted by Wotname

It is a dripless shaft seal; there are various manufacturers - google will help you find the exact one you have.

The only way to fix this properly is to replace it - and soon!!!!!!

When it is working properly, no water comes in; when they fail, it can be spectacularly bad.

HAUL THE BOAT OUT OF THE WATER!

[bernsm]

I'm not an expert on this engine, but a friend had a similar sounding problem when we were cruising last year. It turned out to be a loose electrical connection where the engine kill switch wire attaches to the fuel cutoff valve. I hope this helps.

[Wotname]

Originally Posted by Robert Jansen

Work through the glow plug system. There are any number of minor issues which can prevent the operation of the glow plugs. Start with the fuse. Next in order: the glow plug relay. Third (least likely): the glow plugs themselves. My money is on the relay.

The Yanmar 2QM20 does not have glow plugs; otherwise though good advice for engines that do have glow plugs.

[Wotname]

Originally Posted by bernsm

I'm not an expert on this engine, but a friend had a similar sounding problem when we were cruising last year. It turned out to be a loose electrical connection where the engine kill switch wire attaches to the fuel cutoff valve. I hope this helps.

A belated welcome aboard CF, bernsm.

Please allow to me to add to your first post for the sake of accuracy - the OP's engine (2QM20) does not have an electrical fuel cutoff valve, it is purely mechanically operated by a lever and cable arrangement.