3GM NOT RUN IN 10 YEARS

[NakedCity]

A friend has just purchased a project boat and I have offered to help get the Yanmar 3GM running.The engine has not even been turned over for 10 years. I pretty much have a plan to address the fuel system and the cooling system. My biggest concern is trying to preserve and not further damage the pistons/rings/cylinder walls. I'm thinking of removing the injectors and adding a quantity of Marvel Mystery Oil and just let it sit for a couple of weeks before trying to move the crank.
I would appreciate comments FROM THOSE WHO HAVE FACED A SIMILAR CIRCUMSTANCE.

Thanks

[a64pilot]

Your plan is good, but I would not wait very long at all.
I would want some lubrication on the dry cylinders, but if it's seized, it needs to come apart.
Also of course remove the impeller until actually ready to start, and I would put new oil in it of course and spin it with injectors removed a few time for say 10 sec each with a 5 min wait between spins to cool the starter. My goal would be to be sure plenty of oil gets every where before letting it get compression.
Might not hurt to remove the valve cover and make sure the valves are not stuck by slowly turning over by hand first, and if there is a lot of rust under the valve cover, at least the head ought to be removed and a valve job done.
You may get lucky, quite a few do.

[Wotname]

Originally Posted by NakedCity

A friend has just purchased a project boat and I have offered to help get the Yanmar 3GM running.The engine has not even been turned over for 10 years. I pretty much have a plan to address the fuel system and the cooling system. My biggest concern is trying to preserve and not further damage the pistons/rings/cylinder walls. I'm thinking of removing the injectors and adding a quantity of Marvel Mystery Oil and just let it sit for a couple of weeks before trying to move the crank.
I would appreciate comments FROM THOSE WHO HAVE FACED A SIMILAR CIRCUMSTANCE.

Thanks

While this sounds reasonable, I think you will find that the injectors will be difficult to remove - due to corrosion etc.

I would take the rocker cover off and have a look for obvious issues and if none, put it back on, operate the decompression levers and gently turn over the engine by hand while spraying CRC 5-56 or similar into the inlet manifold.

[Steadman Uhlich]

Here is a link to a thread with suggestions for starting an engine that had been laid up for nine years. It was successfully started. Many tips in the thread.

http://www.cruisersforum.com/forums/...ml#post2374282

[lateral]

Originally Posted by NakedCity

A friend has just purchased a project boat and I have offered to help get the Yanmar 3GM running.The engine has not even been turned over for 10 years. I pretty much have a plan to address the fuel system and the cooling system. My biggest concern is trying to preserve and not further damage the pistons/rings/cylinder walls. I'm thinking of removing the injectors and adding a quantity of Marvel Mystery Oil and just let it sit for a couple of weeks before trying to move the crank.
I would appreciate comments FROM THOSE WHO HAVE FACED A SIMILAR CIRCUMSTANCE.

Thanks

Mine sat for ten years out of the boat. (Approx 550hrs run time) 3GM30f
No precautions taken before pulling the motor. Just kept under cover.
I did dismantle the cooling system and clean/ replace anything that looked
suspect. Exhaust elbow had rotted at junction. New Filter, lift pump, sand blast and paint.
I did pull the injector pump and service, only 'cos I could easily.
Bled air, and fired up after a few cranks.
I did manually turn over first to make sure I had similar compression on all three.( no stuck rings etc) I did usual first run checks.
Running now for two yrs with no events. It does get fuel bleed back after sitting awhile (weeks) Doesn't leak fuel. YMMV.

[NakedCity]

Originally Posted by Wotname

While this sounds reasonable, I think you will find that the injectors will be difficult to remove - due to corrosion etc.

I would take the rocker cover off and have a look for obvious issues and if none, put it back on, operate the decompression levers and gently turn over the engine by hand while spraying CRC 5-56 or similar into the inlet manifold.

Wotname,
Do you think it's a waste of time trying to remove injectors ? Any tricks ? Would a couple days of PB Blaster help ? Good suggestion for CRC 5-56 down the intake. Thanks

[a64pilot]

One day you are going to have to get the injectors out.
I'd recommend actually if they have sat for 10 years, that day is today and take them to an injection shop to have them cleaned.
Inject just about any petroleum product into the intake of a Diesel, and it will run on it, usually rather poorly as the fuel timing is way off and it's not usually good fuel etc, but it's still a dry start.

[Wotname]

Originally Posted by a64pilot

One day you are going to have to get the injectors out.
I'd recommend actually if they have sat for 10 years, that day is today and take them to an injection shop to have them cleaned.
Inject just about any petroleum product into the intake of a Diesel, and it will run on it, usually rather poorly as the fuel timing is way off and it's not usually good fuel etc, but it's still a dry start.

Agreed that one day the injectors will need to come out.

FWIW, I wasn't suggesting using the CRC-5-56 to start the engine, as I mentioned, the decompression levers must be operated before using the spray. It is a similar quicker way to get some lube into the top end. And it should only be done while turning the engine slowly over by hand.

[model 10]

If it starts, damage will come from rust in the oil. I would fill it with a cheap thin oil and then change it and the filter right after the first run. Actually the cheaper the beter. Better oil has additives for friction etc.
Can't say enough about pre oiling the engine. Maybe a drill pump on the oil pressure line? Whatever you do, make sure there is oil flow before you start.

[UNCIVILIZED]

I would think that the oil in the pan may either be sludge, with things growing in it, or very thick. So might it make sense to warm the pan externally, prior to pumping the old oil out. Then refil with new oil. Turn the engine over by hand, & repeat the process once or twice, looking at the color of the oil that comes out of it.

I know that oil's not diesel, but after that long it's going to break down to some degree. And you'll need good lubricity to protect the engine, especially once it first gets running. Since there will be a lot of metal & other crud attempting to foul or bind the moving parts in the engine.

And I agree on adding some lubricant to the cylinders manually, along with testing out the valves & rockers. None of that can hurt, & it definitely could help.

[Lepke]

My current boat sat 6 years, no preserving done. 2 Detroit mains, and Perkins & Onan generators. Other than the usual linkage and valve checks, started them w/o problems on the existing fuel in the lines. Then changed the oil, filters and fuel filters.
I'm near 70 and have been starting long idle diesels since I was in my early teens. The biggest problem I had was dead batteries. The surface rust you sometimes see is micronic. Diesels rarely freeze up. Probably the better lube qualities of the fuel. I don't add oil or other mixes to the cylinder unless a piston is frozen. Because of the clearances, carelessly adding too much oil can crack the rings like too much ether. Besides the smoke, with wet exhaust it all ends up in the water.
When I have stuck rings I use Kearney Rust Cutter. Made for power transmission tower workers. It dissolves rust in ferrous metal. Works excellent on badly rusted nuts and bolts. Sometimes on Ebay or Amazon
Also a mild acid works, too. You're changing the oil anyway.

[lateral]

Originally Posted by Lepke

My current boat sat 6 years, no preserving done. 2 Detroit mains, and Perkins & Onan generators. Other than the usual linkage and valve checks, started them w/o problems on the existing fuel in the lines. Then changed the oil, filters and fuel filters.
I'm near 70 and have been starting long idle diesels since I was in my early teens. The biggest problem I had was dead batteries. The surface rust you sometimes see is micronic. Diesels rarely freeze up. Probably the better lube qualities of the fuel. I don't add oil or other mixes to the cylinder unless a piston is frozen. Because of the clearances, carelessly adding too much oil can crack the rings like too much ether. Besides the smoke, with wet exhaust it all ends up in the water.
When I have stuck rings I use Kearney Rust Cutter. Made for power transmission tower workers. It dissolves rust in ferrous metal. Works excellent on badly rusted nuts and bolts. Sometimes on Ebay or Amazon
Also a mild acid works, too. You're changing the oil anyway.

+1

I've done at least a doz petrol to diesel transplants of used Japanese diesels out of crashed cars that have lain around for years. Some not covered, with external corrosion as well. Changed vital fluids and filters etc, never had one fail. Wouldn't expect that with a petrol.
Diesels ARE less prone to bore corrosion imo.
Depends how many hrs they have done, whether been maintained, on what you deem necessary. If you have the budget, time & it makes you happy, have at.

[hellosailor]

If you're going to be cranking that engine without starting it?

Just be aware that if you run the starter for more than 20 seconds, it may need 20-30 minutes to cool down again, or else you risk permanent starter damage. The coils swell up from the heat and then grind against each other. They're really only made for "starting", i.e. a couple of seconds followed by a long cool-down.

A good reason to decompress the cylinders and crank it over manually to get the rings & cylinders lubricated and free.

[Matsubob]

My 3GM came out of a boat that had been half sunk in a storm, so I had to take the engine apart, since one cylinder had taken on salt water through the open valves. The other two were fine.
What I found from that rebuild was the a diesel doesn't seize as easily as a gas engine because of the fuel having more oily property. However, I would avoid putting high viscosity oil into the top end of a diesel because of the high compression.
For an engine that has sat dormant for 10 years, I would change the oil, using Yanmar's recommended oil, and filter.
Then I would disconnect the fuel line and empty the filter cannister.
Then, with the 3 cylinder decompression levers activated, I would crank the engine while depressing the "kill lever". This will keep the engine from trying to start by accident, but it will make the oil pump draw new oil and distribute it throughout the engine, in a natural way, without interfering with the cylinder top ends. (even if the injectors are removed, the head on a GM series engine has "precombustion chambers" that prevent direct contact with the top of the piston. So, squirting oil into the cylinder would, at best, be very indirect, making anything inserted fall directly onto the crown of the piston)
Then, once the oil has been distributed, fill the filter cannister with fuel and install it, bleed the system, and crank the engine, this time, with the idea of starting it.
It goes without saying that if the current oil in the pan has the look of latte coffee or is thick and creamy like peanut butter, the engine should not be cranked at all, and should be torn down because there is the presence of water in the pan, and cranking the engine would only do damage! A teardown would be necessary, without question.
These little diesels are tough little engines and they will provide years of good service if cared for properly.

[NakedCity]

I thank everyone for their input. I have a better feel now for my task ahead.