Filter at sucking end of diesel pipe

[Vedat Midilli]

Recently, while motoring, engine died suddenly. No fouled prop, no air leak, seperator bowl was clean. Several attempts to start failed. So I didn't force more. Thanks to the wind and sails. Returned back to marina, and called authorized Yanmar technician. He said give half throttle and try again. Engine started... And this was his explanation: "They put a filter at the sucking end of diesel pipe inside the tank. A kind of slime develops at the surface of filter gradually, and at last clogs the pores ending with a diesel starving engine.  This may occur in several years depending on tank and diesel conditions. So how did engine start again? The slime releases itself over the pores in an hour and gives way (partially) to diesel flow for some time. You can even blow back to tank direction through diesel hose disconnected from  seperator/filter for a rapid (but temporary) solution. You are not the first, many boats up today came across with the same issue, and I think all new B's will suffer same at an unspecified time. In this case I simply take out, and throw away that filter. We already have a seperator/filter which does the same job much better, and periodically or when necessary we replace it which is obviously easier. "

 

I wonder if anybody had such an experience. I'll apreciate your comments. I am not sure taking a filter out of the system is the only way. Thanks for your replies.

 

Vedat

 

 

(Mine is a 2008 B43)

[Michael Boyle]

Hi Vedat,
I have a 10 week old 43 that had been filled with diesel and on Sunday after sailing for about an hour went to start engine and it started and then stopped, started again with more throttle stopped again third time opened throttle fully and engine ran normally. This occured on three seperate occassions. During Sunday and Monday. Boat is in for minor rectification and a 50 hr service so will follow up with Yanmar mechanic.

I have had problems with diesel being attacked by microbes some years ago particularly if you over winter without tank either not being completely emptied or left full. There is an inhibitor that can be added to fuel that ensures that this doesn't occur. What mechanic is suggesting sounds like something similar and am surprised that he didn't suggest inhibitor. I agree that removing the filter seems drastic as I assume that this filter is to stop any extranious bits of dirt etc from entering system. Tank is plastic so should be no problems with rust etc only water ingress or condensation if tanks not kept full.

Michael

[Vedat Midilli]

Thanks Michael,

I am very much familiar with your complain which I also suffered quite long. It took more than a year to diagnose the cause. It's very common among new B 40&43. Solution is to replace fine fuel filter which leads to air leak probably due to manual feed pump on the filter. They replace it with a non push button type, and also install a by-pass hose from filter to diesel return line for automatic bleeding. From that time I never needed a second attempt to start the engine. This solution was instructed in Yanmar's official bulletin. Your Yanmar mechanic should easily solve this problem.

Coming to my problem, I share your suggestion. Keep the tank full as possible. Add some ınhibitor to prevent bacteria growth.

Have fun with your new B43, as I do a lot.

Vedat

[Michael Boyle]

Many thanks Vedat,

Yanmar are doing a 50 hour service today so I was able to forward your information re the fix. Hopefully they will have all the bits to resolve the problem

Having lots of fun

Michael

[Steve Knight]

The slime at the bottom of your tank is the microbes living in the suspended water in your fuel. Microbe contamination of fuel is a universal problem among users of diesel and jet fuel. The wire mesh screen filter at the fuel line pickup in the tank is probably too fine of a mesh thereby allowing the microbes sufficient structure to plug the screen. An alternate approach would be to use a mesh with larger holes in the screen to allow microbes but not solid objects into your fuel line that could jam and choke off the flow of fuel. The primary and secondary fuel filters would still protect your pump and injectors from microbes. I use Biobor microbiocide with every fuel addition as contamination (and water) can also come from the supply source. One popluar approach to ridding fuel tanks of microbes is fuel polishing. This can be effective with a fairly new boat. For older vessels though the safest and surest solution is to open the tanks and manually scrub them clean. I did this with my tanks. Fortunately the manufacturer installed inspection hatches which saved me a lot of trouble and expense. The entire bottom of the fuel tanks were coated in a thick layer of microbes which had precipitated to the bottom over the years, until their little corpses had built up into a sheet of what resembled blackish peanut brittle in consistency and texture. As I attacked it with a sharp-edged scraper and a stiff brush, it indeed did break apart like peanut brittle and clouds of microbes would rise and mix into the solvent that I had flooded the bottom of the tank with. It became immediately evident to me that expensive fuel polishing was an inadequate measure in that it only removed suspended microbes from the fuel. It did nothing to address the hardened coating on the bottom that released clouds of contaminants into the fuel as I pounded through steep faced seas in bad weather. This resulted in frequent filter changes in a violently pitching vessel while inhaling diesel fumes, and a potentially dangerous situation for the vessel and passengers. Polishing the fuel without inspecting the tanks leads to a false sense of security. The engine will run fine in flat water leading you to think that you've solved the problem. It is only when the sea state intensifies that you discover that the problem still exists. Having manually scrubbed the fuel tanks and adding Biobor to every fueling has permanently solved the problem. The vacuum guage on my Racor primary filter never reads above 4 pounds of suction anymore.

[Vedat Midilli]

Thanks a lot Steve, for sharing your experiences, and giving detailed info. It was very useful.

Since it's a 2,5 yrs old boat I don't think manual scrubbing of the tank will be necessary. Fuel polishing, mesh with larger holes, and use of Starbrite's Star Trone is what I'm planning to do. (By the way, anybody using or have used Star Trone, his comments will be appreciated.)

Vedat

[Steve Knight]

You're welcome, Vedat. I avoid products by branding companies, i.e. they don't manufacture what they sell. Here is a link to the manufacturer of Biobor JF, the biocide, http://www.hammondscos.com/index.php?id=48 , and to their marine diesel additive and stabilizer which incidently also improves the cetane rating of your old diesel which results in easier starting...
http://www.hammondscos.com/assets/files/specs/Biobor%20MD.pdf

Good luck with you fuel system!

[James Taylor]

Stephen
We had the same issue with the 4jh4ae on our B43. Yanmar will support the modification. They remove the fuel filter pump assembly,install some type return line from the new filter assembly to the tank and an increased capacity electric fuel pump. We had this work completed September 2009 and have had no further issues with starting. The problem is not just on the B43's and 40's it is a Yanmar issue in the engine's fuel delivery design. Many boat owners who purchased this engine are having this problem. It will generally happen after you have changed the fuel filter and used the hand primer a few times.
The line to the fuel tank off the fuel filter after modifications is supposed to be an auto priming modification thus the elimination of the hand pump.

[foster]

hello,

could you publish the content of the bulletin. do you all have B43 buit in USA or some french manufactured ?

I had heard of plastic fragments from drilling the polyethtylene tanks to install the fuel gauges obstructing fuel lines is this the same thing ?

Thanks.

Denis
s/y HIBERNIA

[James Taylor]

http://www.cruisersforum.com/forums/f54/solution-to-yanmar-4jh4ae-s...

"GLOBAL TECHNICAL BULLETIN

Ref No: GTB2009002
Date: February 9, 2009

GTB2008-002
To: XXX XXXXXX marine distributors
Subject: 4JH4-AE fuel system

Yanmar wishes to inform you, that we have found occasional starting trouble on our 4JH4-AE engine
series. After investigation we found that in some rare cases, air can enter the fuel system. The reason for
this was found in the fuel-filter with priming pump.

For this reason, Yanmar has decided to change the fuel-filter and fuel line specification for the new 4JH5
engine series."


Foster
Our boat is a US model 2008 B43 with the Yanmar 4jh4ae and as previously mentioned this is a Yanmar 4jh4ae issue, not a Beneteau issue.
It seems to be a hit or miss type problem. Some engines develop the problem others don't. If you should develop this starting problem you now have the information as to what is wrong and what to do. Yanmar is fully aware of this issue. If your engine is under warranty they will pay if it is out of warranty I am not sure if they will pay.
James

[foster]

Thank you we will keep this information in mind. For the moment no problem starting the yanmar.

Denis