[thedigitalforge]

Dear Group

I'm having a little difficulty starting my old Yanmar YSE12. It used to be a breeze, but just recently, it's taken several attempts. A member of my yacht club suggested a dirty injector. My question is: how difficult a job is removal end cleaning? Any guidance appreciated.

Thanks
Jim

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[mhfowle]

The injector is removed very easily. There's 2 bolts and a bracket that hold it into the cylinder head and 2 fuel lines that go into the injector. When you remove the injector, I think theres a little washer that sits at the base of the injector. Don't lose it. I think a new injector is about $100. You can also have them servived at a diesel engine shop.

Don't be so quick to blame the injector. Hard starting may be due to other conditions to such as: low battery, slow cranking starter, air in fuel lines, low compression, etc...

 

[thedigitalforge]

Tracking down the cause

Thanks for the tips. I think compression is fine and cranking speed/battery are OK - battery x 2 with solar top up cranks the engine as well as it ever did. The other suspect I have is the fuel feed. To stop the engine I pull the throttle all the way back to starve it of fuel. I leave the boat with the throttle in this position. I'm wondering if this allows the fuel to evaporate or drain back.

Basically, I crank the engine decompressed for a second or two, then compress and continue to turn over for a few seconds. Then I wait a few seconds and repeat. Usually 3 or 4 times.

Is there a way to further diagnose?

Thanks
Jim

 

[SteveInMD]

My first guess is either a clogged fuel filter or an air leak. I'd change the filters and make sure all the connections are tight. The filter is a common place to have an air leak.

The diesel is in a closed system and cannot drain back or evaporate unless you have a leak. If you have an air leak, the more time that passes between running it, the harder it can be to start it.

If you do want to 'clean the injector' you'll want to remove it and send it off to be rebuilt. Mack Boring is one place that does this. Your service manual will tell you the interval between rebuilds. I believe it's 600 hrs for my 4JH2E. When removing the injector completely remove and do not bend the metal fuel line.

 

[eightpoint3]

I too am having trouble starting a Yanmar YSE12

I recently purchased a Mariner 28 that has what I believe is a Yanmar YSE12

First, let me say that most of my old sloops have had Atomic 4 gas engines in them with the execption of an old Volvo. I am am new to the diesel world and would appreciate any tips that you have.

Initially, I had an issue where the enging lost the return spring that sits behind the timing chain and the previous owners brother attempted to adjust timing to get the engine running. I had the spring and a mechanic that I hired figured out the springs use and discovered the timing issue.

The engine at times now behaves like I have a dead battery. I'm cleaning connections and looking at the ground on the engine block but it may be a starter. What do you guys know of this problem on this engine? Is that likely. I saw one post here from thedigitalforge is indicating that he gets the engine turning uncompressed and then compressed. I don't have any linkage to do that from the cockpit and would appreciate some details on how your controls are wired up.

 

[eightpoint3]

I too am having trouble starting a Yanmar YSE12

I recently purchased a Mariner 28 that has what I believe is a Yanmar YSE12

First, let me say that most of my old sloops have had Atomic 4 gas engines in them with the execption of an old Volvo. I am am new to the diesel world and would appreciate any tips that you have.

Initially, I had an issue where the enging lost the return spring that sits behind the timing chain and the previous owners brother attempted to adjust timing to get the engine running. I had the spring and a mechanic that I hired figured out the springs use and discovered the timing issue.

The engine at times now behaves like I have a dead battery. I'm cleaning connections and looking at the ground on the engine block but it may be a starter. What do you guys know of this problem on this engine? Is that likely. I saw one post here from thedigitalforge is indicating that he gets the engine turning uncompressed and then compressed. I don't have any linkage to do that from the cockpit and would appreciate some details on how your controls are wired up.

I am attaching a very bad picture of the engine from my phone camera. Where is the Yanmar plate mounted on this so I can confirm the model etc?

Thanks a million guys!

 

[eightpoint3]

By the way, the engine will not start at the moment and acts like I have a low battery...

 

[thedigitalforge]

Hi eightpoint3

My decompression lever is on top of the cylinder head. I think it's just a mechanical link that lifts the exhaust valve.

I have recently installed a new starter motor (not genuine Yanmar, but a Hitachi OEM replacement) and this has changed the starting behaviour of the engine. I think this starter turns slower than the Yanmar, but has more torque. In any event, I no longer have to decompress the engine to start, but I do need a tiny squirt of 'EasyStart' in the air intake (ether) to get her going now. But she does start very easily then.

I know 'EasyStart' is supposed to be bad for old diesels, but I think this is really only true in Diesels with glow plugs. In the case of my old YSE12 it works just fine. An old military friend of mine told me that old diesel powered tanks used to have to be started with ether canisters so it can't be that bad for it.

I have also bought a Tohatsu 5HP auxiliary in case it ever lets me down at sea (never has done yet though). Feel free to ask any questions - I'm happy to help if I can. Do you have manual for the engine? I can sent you one if not.

Cheers
Jim

 

[thedigitalforge]

BTW Yanmar plate is on top of the gear box behind the block. This sure looks like a YSE8 or YSE12 with a hand cranking starter attachment (I wish I had that BTW!!) Is there a hatch on top of the engine you can open to look down on it?

 

[eightpoint3]

Yanmar YSE12

Hey Jim,

Thanks a million! No, unfortunately, there is no access plate to look down on the motor. I am reaching down through the locker in the cockpit and sticking my digital camera in and taking pictures. I will see if I can capture the plate and confirm the model. My old survey indicates a 12hp engine but
The shot that I showed you is of course from the cabin. My problem is likely one of my inexperience with the engine. As I read here about turning it over decompressed and then compressed until it starts, it reminded me that there is a button on the control panel that I have not used that is connected to a solenoid on the right side of the engine near the alternator/generator (can't remember which one it has..LOL) That has a return spring (the one that came off) on it. Perhaps I have just been lucky getting the thing to start at all without decompressing it...LOL

I have been starting by turning the engine on and waiting a bit then hitting the starter. It turns over and starts about half the time but acts like I have a low battery. It makes more sense to get that flywheel going. Since you can't be in two places at once, that control must be the remote decompression control. I believe that I have the starting handle in the boat too which is good.

If you happen to have a manual that you can send as a PDF, that would be very helpful. I will get to know this engine over time but right now, I need to know that I can move the boat on an 8 hour trip and know that the engine will restart once I am underway. I guess I could use that Boat US Towing that I have been paying for all these years...LOL

I will head over tonight and see if I have been ignorant and now know enough to reliably start it....

Michael

 

[eightpoint3]

Still Have a problem

Well unfortunately, that was not it. I am pulling the connections from the starter and looking for problems and will pull the starter and check it if that does not cover it.

 

[mitiempo]

Michael
The button on the control panel is probably the stop solenoid. When activated it will shut off the fuel supply. Diesels always are stopped by cutting the fule supply and this is either done with a solenoid, either separate or rarely integrated with the ignition key, or by moving the throttle back past idle. I have never seen a diesel with a remoth decompression lever. You said there is a spring missing? That could be the problem if the fuel is shut off it will never start.

 

[eightpoint3]

Yanmar YSE12 Not Starting

I'm going to look at the decompression lever this evening and see if she will spin up after using it. I'm running a replacement ground to the engine block and will retest in the normal mode. I'll pull the starter and have it tested too. The electrical control is evidently to kill fuel. I can do that with the throttle control.... not sure what it accomplishes...

It is at least good to know that I can start the engine manually. I will try it and see if I get a heart attack cranking the thing.... single cylinder should not be too bad... I used to manually start an Atomic 4 back in the day... but that was back in the day...LOL

 

[eightpoint3]

Brian,

I answered an earlier comment but did not answer yours. Yes, it is a fuel stop control. The there was originally a hole on the engine body that the spring had worn through to make a slot and later to cut all the way through and fell out and yes... that did stop it from starting...LOL The original owners brother started messing with timing to fix it. The mechanic found the problem and made a temp fix to install the spring and I put a little insert in there now that I can always push out and replace if the spring starts wearing through it again. Since the engine was started in the past without the decompression being activated, it seems to reason that the problem is a bad power connection or a bad starter. I am seeing them on the web for about $125 and it might be an item to keep on hand even if the problem is elsewhere...

Thanks for the tip on the decompression level. I was seeing posts about it being used for starting and was wondering why I had no remote control of it if it was normally used....

We will be moving the boat one way or the other this weekend... now where is that hand crank? LOL

 

[dabnis]

Digital,

I had a VW diesel for a number of years. I used Power Service
diesel additive from the start and in over 100,000 miles never had
any fuel related problems. Before tearing into the engine you might
try using it or a similar type of additive. You might want to do
some research on various types of additives as I understand some
of them may kill the algae type of deposits that may be in your
tank which may end up clogging your filters.

Dabnis

 

[thedigitalforge]

Diesel Additive

Hi Dabnis,

Thanks for your advice. I have decided to try 'Diesel Magic' injector cleaner by Coma before pulling the hardware apart. Will let you know how it goes!

Cheers
Jim

 

[fredyse12]

I have the same engine. Yanmar YSE. Manuals scheepsmotoren marine-engines download
her do you find manual. Just ask if you need some help.