How to Handle Diesel Microbe and Algae Bloom – 1976 43DC

[sgharford]

It’s hard to believe I never had this problem in 30 years of owning diesel boats, but I just had my first ‘algae bloom’ in the port fuel tank on my 1976 43 DC. The ‘sludge’ appears really bad -it’s clogged both the port main engine fuel pickup as well as the separate generator fuel pick up in the tank. I took apart the main Dahl filter housing and saw all the sludge in bottle of the bowl - it's thick and meaty. I just ordered “JF Diesel Fuel Additive” as a biocide that should come in Wednesday to stop the growth.

So where should I go from here? I do not have any existing access ports in the 200-gallon fiberglass tanks. I attached pictures of places I have access to tank to cut or drill holes for access if needed. When I put a tube down the fill tube, there is a baffle halfway down that limits the tube size to about a ½” to snake it around and get to bottom. I bought a heavily discounted and Seaview cheap oil change pump from local West Marine (going out of business - sad). I got it to pull fuel out of tank after priming it (about 8’ head pressure). When I get tube right to bottom of tank it appears to clog.

So, what do you guys think I should do next? The marina outsources fuel polishing, but sounds like it has not happened in a while. I think they will be cool if I find someone on my own on Long Island, NY and pay the marina their vig. I just want to get done as quickly as possible with least amount of work. Thanks everyone – it’s been a long time since I’ve asked for help

 

[Captain Ralph]

What has changed?
First; Where did this come from.
When I bunker, I take on fuel in both tanks. Not a vendor issue for me.
I chased a water issue in my stern tank for a couple of years and finally found a bad deck fill / deck sealant failure. Hose clamps rusted aweigh and the hose turned into a funnel letting deck water into my aft tank.
From that issue, I discovered snake oil just makes snot and clogs the filters with more snot.

Find the source of the water first and then polish your tank.

The better shops that preforms the polishing service know where to draw & return in your tank.
This may include removing a pick-up or two to find that low tank spot.

But this is squab service till you figure out where the issue came from.

 

[Boatsb]

Call Derek for help

 

[Bob Bradley]

If you can get the snot to pull thru your pickup and existing fuel line, perhaps you could pump and polish the fuel into 55 gal drums. After processing what you can get, add a high dose of biocide to the fuel you have removed, refill the tank with it and repeat the process as necessary.

I have a system I built several years ago. It's 2 racor filters in series with a strong pump inline. I'm in central CT, and you're welcome to borrow it. Get a case or two of filters and give it a shot.

 

[Avenger]

I have a pump/filter you can use as well, although Bob's sounds better than mine.

Since you can access the fittings I would consider pulling a fitting and sticking the suction tube directly in the tank. You can use the engine return or pickup to circulate the polished fuel back to the tank.

It helps to get the suction all the way to the bottom of the tank because the engine standpipes usually leave a little room in the bottom of the tank. Basically using the tank as a pre-filter.

Capt Ralph is right about checking your deck fills and vents. It's possible you just picked up bad fuel, but if water is getting in the fuel, the problem will reoccur if that isn't resolved.

 

[edward]

What is the price for fuel polishing ? Per gal or per job ?

 

[SKYCHENEY]

What is the price for fuel polishing ? Per gal or per job ?

Probably per owner. Whoever is the biggest PITA gets the highest price

 

[sgharford]

Thank you everyone! Capt Ralph, you are so right to look for cause. I'm pretty sure the cause is partially me. We've had a real bird problem at Marina this year - they have been pooping all over my outdoor carpet at the lower helm of my 43DC. I've put the hose on the carpet heavy twice, pushing crap off the back deck - right in line with the two fuel fills on aft stern corners. The rubber o-rings appeared good on problem tank, so I've been perplexed. I could see how hose clamp coming off could act as funnel, and know how to access that area by removing panel in aft cabin closet - so I will definitely do that next.

Bob and Derek - Thank you so much for offering to lend me your pumps! It's a pretty expensive endeavor to put one together from scratch, and being this is first time in 30 years and I already have a mountain of obscure tools I forget I have, borrowing sounds like potentially good option.

I have an electric fuel pump hooked up to my Onan generator. I disconnected outlet and put into a bottle, and ran it - but it quickly clogged at fuel inlet in tank. Maybe I add biocide and give it 48 hours, then blow air and try to clear that clog and try again. All the filters are in place if I could get this to work, but the pump may be too small. Will report back!

 

[Captain Ralph]

This is what happened when I added a bunch of snake oil to my aft tank.
Don't be in a hurry to ad stuff to your tank.

 

[Captain Ralph]

That was the aft thank fuel pick-up and screen.

Also, I have to ad, fuel pick-ups are not at the tank bottom. They are up just a bit so they do not draw the anticipated poor fuel. That is why you read tank capacity vs usable fuel bunker in the better notes. Using them to polish fuel will not offer the best results.

A wand to the very bottom of the tank, is where the water and poo is collecting.
The expense of this is based on how to get to the bottom of the tank, past surge baffles and other obstructions.

I finally found a path to my lowest part of my aft tank, this is what I was pumping out;

 

[Captain Ralph]

Unlike adding alcohol to a gas engine fuel system, please do not get in a hurry to ad snake oil to a diesel fuel system, like I did..
Fix your issues, get a real fuel tech on site.

 

[Bob Bradley]

I agree that biocide will cause nasty gunk, but you do have to kill the algae or it won't go away.

 

[Captain Ralph]

I agree that biocide will cause nasty gunk, but you do have to kill the algae or it won't go away.

In small cases, kill and filter it out.
In big cases, you have to call in a big pump and get it out.
I did not realize how bad my issue was until the bow came up,,, all the snot went to the back of the tank to the awaiting fuel pick up. The forward end of my aft tank is 8+ feet aweigh and 6+ inches lower. Where all the snake oils and stuff were collecting.

Many years later, when our bow has to come up and gets bounced around well, I know the Racors will be full of old snot and am ready to service the elements next opportunity.
Add any more snake oil, HECK no..

 

[SKYCHENEY]

There is a difference between a biocide and an emulsifier. The emulsifier will make snot. The biocide will kill the algae. Unfortunately, many combine both. You want just the biocide and it will make little black pieces out of the algae but no snot. The dead bacteria can be filtered out.
Diesel Kleen Bio Kleen will kill it. Don't use the one they make with the green label called Clear Diesel. That is the emulsifier.

 

[doc g]

Or use Biobor JF which is a strict biocide …….Pat

 

[sgharford]

I have Biobor JF coming today I was planning on adding it to stop the growth - I just looked it up and appears to be just a biocide, not an emulsifier or demulsifier. I've been using Diesel Kleen for past 17 years (Sky Cheney - you mentioned you used it about that long ago and I figured if good enough for you good enough for me!) and never had a problem. I ordered a case of it two years ago and they sent me 'Howe's Diesel Defender" instead. I looked it up and seemed OK so been using that. in my original Cummins 903's (dare I tempt fate and say out loud I love those engines). I just looked up Howe's Diesel Defender and it is also a demulsifier (separates water) and not a emulsifier (suspends water in fuel). So not to throw Howe's Diesel Defender under the bus, I think I caused this problem with excessing hose spraying in vicinity of fuel fill.

Capt Ralph - Thank you for sharing pictures of fuel pickup and dangers of adding snake oil, along with what you added Bob. Question regarding the fuel tank pick up and return (picture below) - if I unscrew the 90 degree elbows - does the whole pickup tube come out with it? If so, any advice how to best loosen this 50 year old fittings? Just a few shots of PB Blaster perhaps? This looks like the best place to get access to bottom of tank.

 

[HahnR]

Unscrew the 90 deg fuel pickup fitting out of the tank and pull it out. Whatever polisher you use, make sure it has a pickup line longer than the tank pickup. Measure the tank pickup line & make some sort of mark on the polishing pickup line so you'll know when you've gone deep enough in the tank. There is a baffle with a hole in it the pickup line goes through. Stick your polishing pickup line in the tank and poke around until you find that hole (that's where the depth mark comes in). Drop the polishing pickup all the way to the bottom of the tank, then pull it up slight;ly so you can suck the crap out. You can run a return line from the polisher right back to your fuel fill. Pump till you get clean fuel, then drop the pickup line as low in the tank as you can & not starve the pump

Hope that helps,

Randy

 

[Bob Bradley]

The pickup on mine is a piece of iron pipe. 1/2" or so. Makes it easier to get to the bottom than with flexible hose. Biggest problem is the baffles preventing you from moving it around much at the bottom of the tank. It probably would be helpful to jet returning fuel around in the tank to stir up residue at the bottom. I would think that removing all but the last few inches at the bottom of the tank would facilitate the process.

 

[Captain Ralph]

The pickup on mine is a piece of iron pipe.

Bob, I do not think this is a normal install.
Thru all I have worked on, repaired, installed and updated; A soldered on copper tube/pipe has been standard practice.

 

[brettportzer]

I think he means his polishing device.