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Old 18-09-2010, 08:30   #1
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How to 'Get By' / Diagnose Fuel Problem ?

Hi all,
We were motoring for the last two days, 3 hours on the first day - and then around 3 or 4 hours yesterday when the engine died. I started it back up again and after a few moments of less then optimum performance it was fine. We ran for another 4 hours and it died again - after a couple of momentary skips - and this time it started up again but died two more times after a minute or two.
Temperature and oil pressure were fine, and at first I suspected prop fouling - but I can rotate the prop by hand this morning. So I am assuming I just have some gunk in my fuel. The seas were fairly rolly at times.
I don't have inspection ports in my tank, and I am wondering what the best workaround I can do is...
I have spare primary and secondary fuel filters, should I just replace these every time it happens until they catch all the gunk?
Should I sit here and run the fuel from my tank - hopefully catching issues while on the mooring? (Although there won't be motion to stir up the sediment)
Are there any additives I should put in to help with this?

Thanks for any tips you might have, getting the tank scrubbed would be tricky.


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Old 18-09-2010, 08:45   #2
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Inspect your filters for debries and water, that will tell the storry

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Old 18-09-2010, 08:53   #3
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First, get some diesel fuel bacteria biocide and shock treat your fuel system the next time you add diesel. Like this.. After the shock treatment, keep adding the biocide each time you add diesel as a preventative measure.

Now you have to remove the dead bacteria. This can be done in a few ways. You can "polish" your system yourself or pay someone else to do this. This will eliminate much of the bacteria in suspension but it will not eliminate what has settled in the tank. Your other option, (and you really don't want to have to do this) is to drain your tank, open up the access port and wipe it clean, that's if you have an access port. You should either do this or get a dual filter system.

The last thing to do, and probably your best option, is to buy a Racor dual filter system. What this does is allow you to switch filters while the engine is running without introducing air into the system therefore killing your engine. Get a Racor system with the vacuum gauges so you can determine when it is getting close to needing to switch to a new filter. Getting a filter system with a water sensor alarm is also a good idea. A fire bowl under the sight "glass" (actually plastic) is also a good idea.

You will go through a few filters before removing the dead bacteria that is getting in your fuel supply line from your tank. Fortunately, the filters are relatively cheap and with a Racor system very easy to change out.

Use the same or lower micron filter as what the engine manufacturer recommends. Do not use a larger micron filter than the secondary filter on your engine, otherwise you have just defeated the purpose of the dual filter system when your secondary filter becomes clogged from debris that that your primary filter did not catch.

The dual filter systems are a bit expensive but I think they are the best thing going as far as providing clean and reliable fuel fuel source to keep you engine from dieing.

Unrelated but an excellent idea is to set up a remote pull cable system so that you can shut off your fuel at the fuel tank supply valve. Boats have burned to the water because a fuel line ruptured and there was no way to turn off the fuel at the source because of the flames. This valve should be supply valve at your fuel tank.

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Old 18-09-2010, 08:56   #4
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Sounds a little familiar.

When I let my tank get down to half and get in a chop it will stir up the bottom and eventually stall.
I break the connection between the tank and the primary and blow some air into both ends of the lines and it's usually good to go. The problem is not the filters it's the pick up line. The issue is that you can't have that happening in an inlet or navigating tight quarters. It's happened to me twice in five years, this last time while trying to get through two bridges. Not Good..Luckily I was able to sail through with the roller furling. I won't be that lucky again.

My solution will be to pull the tank at the end of the season and evaluate for either total cleaning or replacement.

Can you access your pick up line? Have you drained any nasty stuff out of your primary?
Was your fuel tank full or nearly so? I'm guessing that if you have a CD it's an older tank and it may be time to yank it and either clean or replace.
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Old 18-09-2010, 08:59   #5
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The long term solution is to remove all the fuel, polish it or at least put it though a Baja filter and then install a inspection/cleaning port. If you have a jelly like sediment, bits can be picked up, block the intake and sit there until the engine dies, then the suction is released and the plug fall back into the fuel, waiting it's moment for you to relax and stop cursing. Then, of course, the same thing happens all over again.

The message is the journey, we are sure the answer lies in the destination. But in reality, there is no station, no place to arrive at once and for all. The joy of life is the trip, and the station is a dream that constantly out distances us”. Robert Hastings, The Station
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Old 18-09-2010, 11:12   #6
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Thanks, the advice is much appreciated.

That dual filter sounds great, albeit a bit expensive. Anything that makes swapping the filter easy would be nice. We were close to Manasquan inlet when it happened the second time, and I did not fancy going below and trying to replace and troubleshoot the system as it was rolly and getting dark. I didn't want to risk firing it back up and motoring into Manasquan either as swells from hurricane Igor were making that entrance a bit hairy. My gold membership with Towboat US is the best money I ever spent on the boat.

For some reason the yard replaced my Racor with a Wix filter. I still have my racor and spare filters here. I am going to replace the primary and run the engine for a while. The engine ran fine this morning with the old filter in flat water, so I fear I may have that recurring jelly sediment issue that fishwife describes.

I'll see if I can access and blow through the pick up line. I'm going to take the Wix primary off in a few minutes and see what it looks like.

We motored for 8-10 hours of the last couple of days so I'm hoping the fuel isn't that bad. Maybe as Tempest described it is the extra slopping from the half-full tank that stirred things up. The tank itself is not the original that came with the boat. It is a SS tank installed around 2002 I think.
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Old 18-09-2010, 11:18   #7
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Do yourself a favour, bite the bullet and install an inspection port in the tank and clean the tank and your fuel. Good luck.
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Old 18-09-2010, 11:19   #8
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Here's what we do, and we've never seen any signs of water or visible contamination in our Racor fuel-water filter or engine filter.

1) When we took ownership of our boat we pumped diesel off the bottom until we removed all the sludge and contaminants. This worked for us b/c our tank was already fairly clean, and we verified it by pumping it through a filter. If I had any doubt, I would have emptied the tank and wiped it clean.
2) Replaced all filters.
3) Since then we've always used a fuel filter funnel when fueling up. It takes a few extra minutes, but it keeps water and contaminants out of the tank. It also let's us know which marinas are passing free water and crud in their fuel!
4) We add biocide whenever we refuel.
5) With our previous boat we used to "pump off" contaminants and water from the bottom of the tank during winterization, or prior to an extended cruise. Since using the funnel fuel filter with our current boat, however, this has been a perfunctory job. The tank has been as clean as a whistle.

You can use a dual filtration system and carry all the spare filters in the world, but it won't do any good if you have a dirty tank.
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Old 18-09-2010, 12:00   #9
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Here's the old primary....

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Old 18-09-2010, 13:20   #10
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Might try

Use a hacksaw and cut the outer shell to expose the element. Take a good look deep in the folds.
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Old 18-09-2010, 13:44   #11
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Aside from all of the above, more or less, I also use a day tank to feed the engine directly--fuel is pumped from the main tank, through the polishing filters and into the 40L day tank. The engine draws off the day tank, the fuel in which, being cleaned and polished, does not overburden the engine filter.
'Tis evening on the moorland free,The starlit wave is still: Home is the sailor from the sea, The hunter from the hill.
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Old 18-09-2010, 14:23   #12
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It sounds like either gunk or air in the fuel system.

You don't indicate the model of external filter, but I've always been partial to the ones with a clear bowl. A look at that will indicate any water or heavy gunk. I also have a vacuum gauge on the external filter assembly to tell me when the filter is getting clogged.

With all the rolling, chances are some gunk came loose and got picked up. It's possible that the pickup tube could be either partially plugged or have a small hole in the side, allowing air to enter the system.

You don't indicate the filter size for the externals, but I use 10 micron ahead of a 2 micron. The 2 micron has the same filter characteristics as my engine filter. I installed it because of problems bleeding my engine and thinking that if I caught the gunk before the engine filter, I'd change the tougher one less often.

I've had similar problems and I had to empty the tank, clean out what I could and pressure clean the rest of the interior. I chose not to polish or recycle the fuel in the tank I (only a few gallons left). I filled with clean fuel, replaced the filters and bled the engine. I'd suggest adding a vacuum gauge to the external filter system as well, and monitor the bottom of the fuel filter for any signs of contamination. You might get some as the gunk can reside in the lines as well.

I'd make sure to add some diesel conditioning and develop a strategy to prevent gunk/water/stuff from getting into the tank.

One other thing to check is the low pressure fuel pump. They can go bad and give unusual indications.
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Old 18-09-2010, 18:30   #13
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Had a friend with an S2 sailboat , had a marinized VW deisel eng. On one of our trips together , every few hrs his engine would die. After 2 filter changes with no Longer run time (that filter was plug-in up fast we thought) we cut the filter apart and it was brand new inside. Traced the supply line back to the tank and found a fitting we could not explain. Took it apart, a ball check valve, apparently a requirement for gas eng on a diesel boat.Removed the check valve it had a piece of rubber in it and the eng ran fine. Totaly left field but it happens.
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Old 19-09-2010, 05:48   #14
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Thanks again,
I'm considering getting a vacuum gauge, a clear bowl for the racor (30 micron) and getting the fuel polished.
I understand that getting the fuel polished is no substitute for removing and cleaning the tank, but unfortunately I don't have the time for that now.
I would consider getting dual racors so I can swap one out while still running the engine, but that won't do me much good if the pick up line is getting clogged.
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Old 19-09-2010, 06:56   #15
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Before you get too far making changes to your fuel system, you should pull out the pick-up tube from the tank and check if there's a screen at the bottom. There should be no screen in a diesel tank, but many installations have them. Any gunk in the tank will get trapped on the screen and disrupt the flow. If there is a screen, it should be a simple matter to remove it.

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