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Old 21-05-2022, 15:46   #1
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Unseized Yanmar 2ym15 no compression

Inn 2019 December I got ill and was only able to get back to boat in April 2022 this year and ,the Yanmar had siezed up

The 2006 Yanmar had preformed well for 150 hours during months from July 2019 to November 2019
The typical use was 50% gas to recharge batteries or to drive 30 foot 1968 era sail boat at about 3..5 knots with 3 blade prop 12x9.

I removed crank case oil in 2019 then unfortunately I ggot a long term sick issue until April 2022

In May 2022 with taking off the injectors and putting every know oil from diesel to easing oil and brake fluid oil type 3 and lots of force from crow bar and bolts onto the crank wheel I got the seized up engine to move slightly .
Gradually with rocking back and forth and many hours I got engine to turn over

I did suffer a lot of hydro lock issues and squirted out the excess excess oil in the cylinder through the open injector holes with small turns of motor typically about 1/4 revolution

I resembled a engine and it seemed to lack compression
Repeated attempts by me to start engine failed but all indications are fuel is getting to engine .
With an injector removed it seemed to spray fuel from that injector and fuel seemed to get to both the fuel pipes when I cracked the fuel supply pipes


Any ideas what is the most probable reason for this issue would help

As I am based In boonnies lost in west Ireland where. real marine mechanics only do rich boats and charge telephone numbers that isnt a option and probably cheaper to buy another engine I recon .


I suspect eiither the piston rings are broken or are carbonised so don't open up correctly or the valves don't close properly or might have got bent or don't sit properly or the injector seals are broken or worse something real bad has occoured

The engine turns over no problems fairly quickly but won't sttart even with injecting quick start ether fuel into the air intake. When quick start is injected in there is a popping sound sometimes but not much else .

Access to engine is limited under cockpit floor mostly and engine compartment was made for 1968 era small 6 HP petrol engines of that era so larger 2 pot 600 cc Yanmar is squashed into the tiny engine room .


I really would be challenged to remove the tappet covet or head or worse the engine due to lack of access to engine without to cut out the cockpit floor and reglass it back in after doing that work


I bought 2 of the new injector seal but can't get the old seals out .The seals are one copper ring and the a button ring insert and the another copper ring .

The special injector hammer action extractor tool cost. € 120 euro about £100 or $ 110

Any plans on line or ideas to make this injector seal tool extractor would help or more affordable on line version

If I can't fix engine for reasons like it costs too much I would have to look to buy a second hand 6 HP petrol out board motor

Thanks
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Old 21-05-2022, 18:00   #2
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Re: Unseized Yanmar 2ym15 no compression

Not a Yanmar expert but my first thought as I was reading your post was to pull the valve cover and see if you had a stuck valve. As I continued to read I see that there is no top engine access.

My other thought was is there a compression release lever?

Was the cockpit floor cut open to install the engine? Not having valve cover access means no valve adjustment - a normal periodic maintenance item (every few years). Maybe you need to have a removable cockpit floor rather than glassing it in.
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Old 21-05-2022, 19:58   #3
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Re: Unseized Yanmar 2ym15 no compression

It certainly sounds serious. Have you actually measured the compression? If there is not good compression, then the problem is indeed serious at the level of it's got to come out of there for repair or exchange.

Then give thought to whether it should be repaired or should be replaced. With it out you can pull the head and the pan and get a look inside. If you choose to replace it, I suggest that you find another of the same engine, because switching to a different engine means all the stringers, mounts, seacocks, exhaust, cables, hoses, and wiring will be in the wrong places.

Good luck with it.
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Old 22-05-2022, 00:02   #4
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Re: Unseized Yanmar 2ym15 no compression

Thanks for feedback to Stormalong and tkeithla
I have some ideas to chew on

Compression measure devise is big bucks and can't find a rental source

Any ideas on how I to make a cheap version compression tester i am all ears

Is 16:1 compression ratio about 200 bar ??

I don't think these newer type diesel engines with no big flywheel do a decompression lever
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Old 22-05-2022, 00:45   #5
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Re: Unseized Yanmar 2ym15 no compression

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Originally Posted by bouncycastle View Post


Is 16:1 compression ratio about 200 bar ??

I don't think these newer type diesel engines with no big flywheel do a decompression lever
16 to 1 compression is 16 bar. One bar is atmospheric pressure at sea level. About 14.5 psi for us non metric people.

From a few google searches it appears that both the 2gm and 2gm20 series engines have decompression levers.
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Old 22-05-2022, 03:19   #6
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Re: Unseized Yanmar 2ym15 no compression

2YM15 does not have decompression levers.
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Old 22-05-2022, 05:02   #7
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Re: Unseized Yanmar 2ym15 no compression

only one solution, take this engine out of the hold !
a diesel engine without compression cannot start ...
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Old 22-05-2022, 07:30   #8
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Re: Unseized Yanmar 2ym15 no compression

Here go. That's US Amazon at $35, but should be available in Europe as well.

https://www.amazon.com/Paisley-Indus...xpY2s9dHJ1ZQ==
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Old 22-05-2022, 09:13   #9
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Re: Unseized Yanmar 2ym15 no compression

Thanks for all the info on air pressure bar and compression lever and cheaper sources for test kit to test compression

If I remove engine to work on it this season I would have to park it some place for few months and opt to get a outboard motor to keep me going this season . I would only remove engine if I knew it was piston ring issues because in that case if I cut the cockpit floor I can access the head and valves if they are the issue




What gets me is why did the engine seize up after two years to be not used where as in 2019 when I bought the boat the engines fired up no issues after it had sat in the boat yard for five years and never even been serviced or used in five year s


I hope to try to make able to make. a devise that can extract
the injector seals

Also I will try to make a devise that can replace the injector and attach a balloon type device to it and then turn over motor and if balloon fills and deflates that could tell me if the pistons are pumping and the valves are closing .

Even if I order a compression tester from Amazon it could take weeks to get to Ireland as the USA slides rapidly into
a severe fuel crisis and supply chain crisis because they send all their oil to Europe and Ukraine to fight the Russian war

The latest Practical Boat User Magazine has a main article on engine crisis either to buy or sell or repair a broken engine .

It seems that he Kaboda engine has no electronics and might be the best buy for blue water sailors with so many stranded waiting for electronic control systems
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Old 22-05-2022, 15:29   #10
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Re: Unseized Yanmar 2ym15 no compression

If I were to hazard a guess, if you got water in the cylinders, the zero compression is because the rings have corroded slightly and stuck in the piston grooves. Am not sure about Yanma's (even though I have a 3gm20F) but if you can get the pistons out, I bet the rings are stuck. In which case its an easy fix.
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Old 22-05-2022, 15:32   #11
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Re: Unseized Yanmar 2ym15 no compression

Quote:
Originally Posted by tkeithlu View Post
Here go. That's US Amazon at $35, but should be available in Europe as well.

https://www.amazon.com/Paisley-Indus...xpY2s9dHJ1ZQ==
Wonder if it actually fits a Yanmar diesel, as they are not all the same design.
Worth the $35.00
If it does.
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Old 22-05-2022, 15:42   #12
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Re: Unseized Yanmar 2ym15 no compression

I bought a Corvette which sat in a pound for two years. I begged the auctioneer not to start the engine but he did. I deducted 3K off my top bid on the spot. Fuel oil and engine oil can contain some pretty mean acids. The rings valve guides cam followers rockers all have metal to metal contact where they should all have a film of oil.
My best guess is you dropped compression rings snapped in half and dropped the bits in the crank case.
Most engines come out without cutting anything save a corroded engine mount.
You need an inside micrometer to fix on the repair. A piston kit complete with wrist pin rings. Whether you can cross hatch hone a pop a new piston depends on the damage to the barrel. It made need 10 thou and a matching piston
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Old 22-05-2022, 15:48   #13
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Re: Unseized Yanmar 2ym15 no compression

Never re-ring a piston which has dropped a ring. It’s definitely took a hit even if it’s a scratch on the ring groove. Pour some thin weight oil in cylinder and let soak
Replacement motors are not bably priced
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Old 22-05-2022, 16:45   #14
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Re: Unseized Yanmar 2ym15 no compression

Having seen this over the years as a mechanic I'd venture your rings are stuck. Give it a good soak with light weight diesel oil or ATF. Both have high detergent content. A week topping up daily would be reasonable.

Try running it by spraying WD40 into the intake while cranking along with a shot of ether/starting fluid now and then. Don't run the starter for more than about 30 to 45 seconds. Let the starter cool down when it gets hot.

If a week long soak doesn't pull up the compression use 50/50 mix of ATF and acetone or MEK. BUT be ready to change the oil before trying to start it. Alternately you could use 100% LiquiMoly "Diesel Purge" into the cylinders BUT don't let it sit for more than about 4 hours.
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Old 22-05-2022, 17:04   #15
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Re: Unseized Yanmar 2ym15 no compression

What scubaseas said.
Got a tip for sealing injectors if you cant get washers out, use a thin smear of Loctite 518 or Permatex 51813 on face of injector if you have trouble with leaking injector.
16:1 compression sounds low for a yanmar, I thought it would be more like 20:1 but I didnt check, that would be around 400 psi.
If you have access to mains power a hair dryer blowing into air intake with wd40 squirt helps to start it too.
Your rings & bore are probably a bit rusty. Rings get stuck in ring grooves pretty easy.
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