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Dockdozer 09-11-2009 10:00 AM

New Yanmar, hard to start, or just cold natured?
I have a new Yanmar 4Jh4AE. It has just 256 hrs. I have found that you have to use the glow plugs to get her to start every time you start her, or rev her up a little. Is this right? Every other diesel I have had experience with after warmed up will start in a second. Ok I first start of the morning, glow for at least 20 sec, starts right away.(It is in the 80s or 90s) Motor the boat for 45 min to 1hr, to deep water. Engine off sail for 2 or 3 hrs. I reach down and hit the starter and she will start for a few seconds and then die. Now I can glow her again and or sometimes she will still not start until I rev her a little. To me this diesel should be warm for a long time, and not have to use the glow plugs, or the throttle. Now I did talk to a diesel injection guy that said the with the new diesels that are coming out now, that they could be cold natured.
I am not very cold natured, when I reach for the key and she will not start!!!!!!!!
Please help guys!

JohnRPollard 09-11-2009 10:27 AM

Ours is a smaller engine (3 cyl Yanmar) without glow-plugs, but the manual indicates that the throttle should be advance to about 3/4 full throttle when starting.

I would review the starting procedures as described in your owners manual, to see if you are following them exactly. Big diesels can be hard to turn over and glow plugs really help with that.

scottyt 09-11-2009 12:58 PM

i wonder if its and injector tip issue, ie not atomizing properly.

if you can try to try to start it with wd40, the older stuff if you have it. basicly spray some in the intake as some one else cranks its. this might help narrow it down

Dockdozer 09-11-2009 02:22 PM

Thanks I will try the WD40. The diesel injector guy told me that the injectors in some of the the new diesels do not flair, or fan, that it is a direct stream. He did not know about the new Yanmar. And in return could make it harder to start.

Dockdozer 09-11-2009 02:24 PM

I did read the manual but don't remember it saying 3/4 throttle. But I will go back and read it again.

negrini 09-11-2009 03:17 PM

I have same engine with 500 hours. Since 0 hours, I just glow for 7 seconds (its warmer here) and crank with no throttle at all. Recently it behaved exactly as you say, and pissed me for 2-3 months. As part of my regular maintenance I went down and drained the water/fuel separator, and found amazingly 1/2 glass of water (note: this separator is the cheap black one, so I can't see through the bowl). To my surprise, engine went back to the original firing behave just after some cranks on that day. I can't correlate, but I'm glad its back to the normal ....

Dockdozer 09-11-2009 03:53 PM

This diesel has done this since day one. I noticed the PO used the throttle to start it. After I got the boat home I changed one of the racor filters witch was a 30 micron and went back with a 2 micron, and it had a very small amount of trash in it, not near a 1/2 a cup. Then I changed the filter on the engine. I also polished the fuel tank the best I could for over an hour, and found very little trash in it. Now I am thinking of the small filter in line before the filter on the engine. Do you have this small filter on yours? It looks to be just a small in line filter. I don't know if this factory or some one added in. I am thinking that the engine has to many filters. Two Racor 500s, that little inline filter, and the filter on the engine.

negrini 09-11-2009 04:09 PM

Dock, I don't have it in line, and my system goes one water/fuel separator with filtering, plus the one mounted on engine. Another point you should look for, is there any air leak, or wrong mount on fuel return lines just where it enter the tank, that allow for fuel to drain from the line right on injectors ? That was my initial suspicious as if I re-fire immediately after turn it of, it worked with zero throttle. I was concerned on how low the tank was mounted, sifoning the fuel line back. luckly it fixed after that draining.

roline 09-12-2009 09:27 AM

The 2GM20 likes 1/2 throttle and a quick crank to fire up in the summer. In the winter she likes 3/4 throttle and about 3-5 seconds till she fires. We sail all year even in the cold of winter. In the winter season we just re-antifreeze the engine after an outing.

Gary M 09-12-2009 09:52 AM

You may have too many filters. The mechanical pumps only put out about 3-4 psi and each filter causes a pressure drop, however I would think this would show up at higher RPMs. Also if you have a 2 micron as your primary that will have a larger pressure drop than a 20 micron.

In my opinion you just need two filters, the primary of 20 microns and then the secondary, which with my Yanmar is mounted on the engine, and it is a 2 micron. Anymore is over kill. Some people mount two primaries in parrallel so they can swing between them if one gets fouled while running.

My older 2GM starts first crank every time and it does not have glow plugs but I do give it half throttle.

Good Luck

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