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New Yanmar, hard to start, or just cold natured?

10K views 32 replies 11 participants last post by  CanDrac 
#1 ·
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!
Dockdozer
 
#2 ·
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.
 
#6 ·
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 ....
 
#7 ·
Negrini
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.
 
#8 ·
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.
 
#9 ·
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.
 
#10 ·
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
Gary
 
#23 ·
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.
YEP! Fuel filters every time... unless it's a bad pump. My money is on the filters. The number of hours is irrelevant. What matters is the condition of your tanks and lines and where you buy your fuel. The fuel viscosity and combustion chamber temp amplifies the issue. A good diesel additive helps both. Smells better too.
 
#11 ·
Thanks Gary
I am with you with to many filters. I am going to remove the inline filter. How do you know what microns that the engine mounted filter is? I just replaced it with a Yanmar filter, doesn't say. All and all I am going to use a little throttle when I start up. And a diesel guy told me to use a 2 micron filter in the racor, and just change it more often if needed. But the problem was the same with a 30 micron before I changed to a 2 micron.
Thanks Guys!!!!!!
 
#12 ·
To me..

Your loosing fuel prime.. some where there is an air leak and it allowing fuel to return back to the tank leaving the inj pump air ridden requiring the engine to spin longer to " prime back up".. Does it spit and sputter until you give it a bit of throttle and clear up? A little smoke " or it could be a bunch"??

Check any anti back flow devices on or near the fuel pump/or filters.. Change any filters lately? Use a cheaper or different fuel filter? replace any fuel lines? Did not get or dropped the copper gasket off of a fuel through bolt??

Just trying to help.. But this is what i do day after day for 22 years. :)
 
#14 ·
Thanks Dieselboy
Yes I have changed all the filters except the little inline filter close to the engine. All were Yanmar, and racor , racor is the 500 series . The engine starts with the throttle ok and does not spit or sputter and no smoke. I just have never had to use the throttle to start any diesel I have ever had! Check valves is something I need to look into. Should their be a check valve at the filter on the engine. that is the highest spot on the fuel system? Or could I place one their? Dockdozer
 
#15 ·
....The engine starts with the throttle ok and does not spit or sputter and no smoke. I just have never had to use the throttle to start any diesel I have ever had!
Did you have a chance to consult the operation manual?

As I mentioned earlier, our smaller Yanmar is designed to start with the throttle advanced. If yours is too, then you really don't have a problem and the troubleshooting ends there. :)
 
#17 ·
Dock

I have the same engine as you that has now got 3600hrs on it. It starts without any glowplug use within the first 2 seconds on the key. Not once - every time. I had a 3GM30 in my previous boat and had the same start performance. So to answer your question - no, Yanmars are not lazy starters.

There must be something else - I reckon Dieselboy is onto it. There is a bleed-back or slight air leak or something. It's not a characteristic of the engine
 
#18 ·
Thanks Omatako
That is what I thought! John may have something also but I am 80 miles from my boat and cannot get back to it for a week or two. Dieselboy may be on something also, because one time when it would not start right a way, I did bleed the system at the filter on the engine and their was air! So when I can get back to the boat, I am going to read the manual again, and then start looking for air leaks and check valves. So I want to thank you all for the help and I will post back what I find out.
Dockdozer
 
#19 ·
Ok Guys
I looked at the manual and it said nothing about throttle at start up. What I thought was a inline filter looks to be a electric fuel pump I think? Their is a wire running out of it. I looked up racor's and they should have check valves in them. I don't see any thing else that looks like a check valve. I checked every hose clamp and seemed a little loose but she still starts the same. Will run for a second or two and then die. Until you use the throttle. I am going to check the in line fuel pump and look for a check valve.
Dockdozer
 
#21 ·
Steve
This boat is new to me it is a Morgan 383, and the engine was installed in South Florida, and I am in Texas, and were I am located Yanmar specialist are hard to come buy around here. I would have called someone already but the closest one I can find is two hours are better from the boat. I have worked on diesels before and this particular problem has me stumped so far.
Dozer
 
#22 ·
How does it idle? Is it nice and smooth or does it rattle and shake? If you have an air leak it's likely that it wont idle well.

Does it have good power? Will it turn close to 3000 rpms (the rated rpm for this unit)? Make sure it's fully warmed up and the bottom / prop is clean before trying this.

My Yanmar 4JH2E doesn't have glow plugs. Since your motor is designed with them you may have to run them for 20 seconds before starting. A warm cylinder helps, but it's not like a red hot glow plug to fire off ignition.
 
#25 ·
Every thing on the engine was replaced new, from fuel lines from the tank to muffler at stern.
I have replaced all filters. And polished the fuel with a pump and filter system at over 2 gal. a min. for over an hour, 40 gal tank. Found very small amount of trash in the fuel. I have since added a fungicide, and the PO used marvel mystery oil, the diesel is a red tent. I have only added 12 gal. of fuel so far and I bring it from home with a 6 gal tanks. Racor 500, 2 micron no trash in bowl as of now. I have found what I believe to be a in line fuel pump at the engine. Then their is a filter on the engine, and I have no clue what micron it may be. Filters are Yanmar and Racor.
I am with you on the air leak but how do I find it????
And Dieselboy I will give you a call!!
Dozer
 
#27 ·
Hmmm... I still say the issue is fuel pressure, but I'm not there working on it. Diesel fuel systems do work on very low pressure and once drained can take a while to charge back up. Most diesels will not start after a filter change without a lot of ether, which can do serious harm to your pistons and rod bearings, or manually pressurizing the fuel system. Sounds now like a possible leaking injector causing your pressure to drain while shut down. The return line from the pump to the tank could also be leaking down. There should be an spring-loaded type pressure valve in the pump. The only way to confirm most of this is with lots of gauges, pressurizing the fuel system using an alternative method, and watching where the pressure drops (if any) are taking place. It may be time for a pro with all the right tools to have a go at it. Best of luck.
 
#28 ·
Is your starter motor turning it fast enough? I once went round and round with an engine and realized the problem when I heard an identical engine turn over. I never realized that mine was being turned too slowly. New starter fixed everything, but I can see where you may have a good starter, good battery, and still turn too slowly because of connection problems.

BTW: For cold weather starting I lift the compression release, open the throttle, and give her a 3 second spin. Then I close the compression release, and spin her again. Starts right up.
 
#29 ·
The Racor should have a 10 or 30 micron element, not 2 micron. You should change that out at some point but I don't think that's the problem right now. If it were you'd have low power.

Slow cranking is a good thought. Are the starter connections and ground wire connections clean and tight? What does the voltage read at the starter during cranking?
 
#30 ·
I will have to check the starter and connections, the battery was replaced last year with the engine. I am looking for some gauges so I can look for an air leak. Ok a leaking injector? Are you saying a leak at the fuel line going to the injector, or the injector it self? And that is a new idea that the injector pump leaking back down the return line! Thanks Guys for all the ideas were to look.
Dozer
 
#31 ·
With all due respect for my fellow members here...

Looking for a leak...if you have a leak before the lift pump it will be hard to find since it will always be under suction. You just have to go connection by connection and do your best. You could temporarily change our the fuel line leading into the lift pump with clear tubing provided you can find some with thick enough walls so it doesn't collapse. The clear line would show you if you have an air leak before the lift pump. You should see no bubbles with the motor running.

If the leak is between the lift pump and the high pressure pump you should be able to see wetness or dripping fuel.

If the leak were after the high pressure pump you would be running on less than all cylinders, and running rough so I don't think that's the case.

With the hours on the motor you have it's very unlikely to be a bad injector. You can remove them and send them off to be rebuilt, but I think you are barking up the wrong tree.

If you injector pump is so bad that it's leaking back I doubt your motor would run at all. Normally injector pumps do not leak back what so ever. It's also very unlikely the problem at the low hours you have.

You should be able to crack the bleed screw a little on top the secondary filter with the motor running and fuel should squirt out. If not you may have a weak lift pump. Again, this is unlikely since it's a new motor.

If you don't have the Yanmar Parts Manual and Service Manual you should buy them.

You might find taking a class useful. I've worked around diesels for many years, but I learned a lot by taking a level 1 and 2 class on marine diesels. I learned a ton and have put what I learned to good use on my boat.
 
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