Injector issue follow up

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Injector issue follow up

Postby Dieseldame » Thu Jan 03, 2008 7:10 pm

Okay, so the boat sits half full of fuel for the summer, then is filled with fuel and shaken like crazy in rough weather. Racors try madly to keep up depositing fist sized hunks of algae in the bowl about every 10 hours of running, secondary filters got a dose of algae and were changed...then one of the Detroit Diesel's (V12 71 series) got cranky. The back end heated up and started clanging (temps of last two exhausts were twice that of the other cylinders). Changed the injector at the site of the hotest heat and sound of clanging....runs much better. One of the Racors for the engine with the injector issue jumps to 25" of vacume when trying to put it in service...thinking there is a blockage here somewhere. What's the best way to clear this?

Also, what's waiting around the bend? What other work needs to be done to minimize problems later on?

Should mention a single fuel manifold runs the two mains and 2 John Deere gensets. Each main has a bank of two racors, gensets have one.


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Postby JK » Fri Jan 04, 2008 1:15 am

You have bugs in your fuel tank. They grow in the interface of the diesel/water and will form large mats of slimy goop for lack of a better descriptions.
Tank has to be pumped out and pressure cleaned with HOT (70*C comes to mind but I'd have to check) water and hand dried with lint free rags.
You want to keep your tanks treated with something along the lines of Aderco. Good housekeeping is the key here, circulate your fuel, do not let tanks sit for months/years because they are hard to fill (yes it happens).
Take samples of deliveries, yes you will get contaminated fuels from certain bunker docks though the suppliers claim otherwise.
You do not want to add any bug killer products such as Isothiocide (if you can still get it, this stuff is deadly) when you have an issue already. That will kill everything and send it through your system.
I've only ever had to dismantle fuel lines once for a particularly stubborn problem, but your fuel filter costs are going to go through the roof until it is sorted out.

You can renovate the fuel, but it is expensive and you have to treat it ashore. Usually you can swing a deal with the tank cleaning companies for them to take the fuel off your hands and clean the tanks in exchange-if it is enough fuel to cover their costs.

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Postby ArkSeaJumper » Fri Jan 04, 2008 5:57 am

I would agree with all of the above. The temperature 70 is a good starting point, if posable steam clean, and I dont mean the hot water from the presure washer. Real steam
You also need to check your sump (lub oil), Bugs in the fuel will contaminate the lub system as well.

You can buy test kits, dip slides, I cant remenber the company name, but will check if you want.

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Hum Bug

Postby The Dieselduck » Fri Jan 04, 2008 10:10 am

It seems every boat on the west coast always has "Hum Bug" kit. It detects bacteria in your fuel. Its available here ... ... &Itemid=27

Unfortunately you learned the hard way, what poor management of fuel can do - keep the water out, and like JK says, rotate your fuel just like milk at the grocery store. Rotating fuel is sometimes a pain because youre "not allowed to do it"... stability this and that, or senior people say, "thats the way its always been", then all you can do be vigilant for any sign of water.

I don't think there is anything you can do to prevent high filter consumption at this stage. The tanks will have to be emptied and cleaned manually. The slightness residue will promote growth again, you can use a biocide, but get ready to change lots of filters.[/url]
Martin Leduc
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Martin's Marine Engineering Page

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Postby JK » Fri Jan 04, 2008 10:48 am

Just want to add that sometimes this can be caused by your fuel oil purifier as well.
I have seen a belt driven FOP that was not running up to speed contaminate the day tank with water. Add that to a ER staff not checking for water at the test cock and you have an interface plus bugs that have moved thru the FOP.

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Bacteria Test Kits

Postby TxMarEng » Fri Jan 04, 2008 11:06 am

You can use a test kit such as:

Or you can send a sample to a lab such as DNV Petroleum Services for the Combi-cult bacteria yeast and fungi test. In any case if the bacteria is present there is nothing to do but clean the tank. Treatment after the fact does not help. Generally a foul odor is associated with bacterial contamination. Always helps to keep tank bottoms stripped and if susceptible to heavy condensation which isn't uncommon with Detroits due to the high receirculation rate treatment with a biocide may be prudent.

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Postby conrod » Tue Jan 22, 2008 7:49 pm

A company based in Aberdeen Scotland, and in Houstan Texas, Commercial Microbiology, provide a very simple to use bug test kits. Mu mob use them exclusively on out 70 odd boats. We test once a month all the day tanks. If we get bugs in the DB's then we dose with UNITOR Biocontrol MAR-71. Does the trick.

Try a bit of Viladon Filter material in the primary suctions of your transfer pump. Picks out the yucky stuff.

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