Plastic Diesel Fuel Tank

[Issywa]

Last weekend my Yanmar 3JH4E started losing power and as I returned to port, I could only achieve ~1800 rpm. Adding more throttle merely resulted in exhaust but no extra RPM's. I am concerned as the exhaust smoke appeared to have a blue tinge to it. I understand that may be more of an oil burning issue but really hoping it's somehow related to my fuel system. Injectors?

In changing the primary and secondary fuel filters, I noticed a fair bit of material in the primary filter. I did not see any water in the bowl of the fuel/water separator. This prompted me to remove the fuel pickup, and the end of it is coated with debris running up ~1". (pic attached) Thinking this might be associated with me forgetting to top off the tank and letting the boat sit with only a quarter full tank for the winter..... negligence is usually punished!

Ideally, I'd like to clean the plastic tank but it has no access ports to effectively do this. So a couple of questions in no particular order:

1. realistically, can I add access panel(s) into the plastic tank that wont leak? I found a panel (Vetus ILT) but haven't had any luck sourcing it. And am concerned about it actually working. Any others?
2. can I simply add an appropriate amount of biocide to kill the "bugs" and change filters until the tank is reasonably clean - this will probably use too many filters so I'm contemplating some form of "inline strainer" to catch the excess material and avoid using a bunch of filters
3. seems to be a lot of controversy whether to use a biocide on a regular basis - thoughts on this
4. in general, should I be using any cetane booster

I figured I'd tackle the above stuff first before getting into my main concern - the smoking exhaust. Will advise on that later.

[OloteleMtn]

You didn't say how big the tank is, or whether it is removable, but if it is, I would drain it, remove it and clean it out (hot soapy water etc and dried out before reinstalling; change all fuel filters, purge fuel lines, pull and clean the injectors, and bleed the air from the fuel system....that should get you going.

[Issywa]

Draining the tank will be easy enough. And I think removing is feasible. But not sure how to effectively clean it with only a couple of small holes for the filler, gauge and intake/return. I guess if it'
s out of the boat, it would be easy enough to insert a high pressure hose and move it around to try and get all the surfaces clean.

But I'd rather add some access panels IF that is feasible.

[Vasco]

A fuel polisher can get in through the sender and clean the fuel and the tank using a wand and a mirror. Had that done to my 393. After that I used Startron and never had a fuel problem again.

[Compass790]

With our tank ( removable ) used petrol ( gasoline ) to clean that asphaltene stuff out. Just shook the tank around as it's only about 6 US gallon capacity & the stuff we drained was black.
I'd suggest checking your deck fill cap o-ring & replacing if necessary.
I believe some US diesel is below 50 cetane in which case you should use cetane booster
We used biocide once after cleaning & haven't since ( 7 years )

[mvmojo]

If you can get it out you're golden. Use a gasoline to dissolve the gunk in the bottom then use a pressure washer and strong detergent to clean thoroughly. Shouldn't be too big of a job (famous last words!).

[JOHNMARDALL]

John Mardall here for Vetus Maxwell. The ILT inspection and clean-out port you mention is a standard product and a good one which I've installed myself on a plastic (linear polyethylene) tank. The tank will need to be empty before you start as the hole saw will drop some fragments as it breaks through. The hole saw and resulting hole diameter is critical as the seal bulges against the sides/edges of the hole in the tank. If you'd like to tell me where you're located I'll give you the name and contact information for the nearest dealer. Direct contact: jmardall@comcast.net.


All the best
John Mardall
for Vetus Maxwell Boat Equipment.

[a64pilot]

Originally Posted by Vasco

A fuel polisher can get in through the sender and clean the fuel and the tank using a wand and a mirror. Had that done to my 393. After that I used Startron and never had a fuel problem again.

You can certainly install your own access port, if there is room to do so and clean out the tank yourself, but the post above is I believe the easiest answer.
I’m of the opinion that regularly adding a biocide will prevent most problems.

I would remove the stainer which will mean a longer dip tube, first strainers are not necessary if you have filtration which of course you do, its better for the junk to get into the filter and then you change it rather than clogging a strainer.
Plus a strainer like you have means there is a coupe of inches of unused tank that will eventually fill up with junk or water because you can’t suck fuel from the bottom, replace the tube with one that comes very close to the bottom and then if you get any junk it gets sucked out before it builds up into a mess.

Someone will soon tell you that you need a fuel polisher and if you had one this wouldn’t have happened.
Maybe, but especially if it pulled from a dip tube like the one you have, then it won’t pull anything from the bottom of the tank and junk would still build up.

I don’t believe your problem is asphaltanes But most likely biological, you need to add a biocide at the shock level and let it sit awhile before the fuel polisher comes, you want it dead, and he will suck out the dead bugs, then add biocide every time you add fuel. If you don’t kill them they will continue to grow and your problem will reoccur.

So far as controversy on using a biocide regularly, that’s from people who don’t know any better, in fact if you buy many better fuels they have a biocide in them anyway, Valvtec does, every bit that is sold, but many if not most Diesel doesn’t, it cost a bit more of course and every penny saved is a penny earned if your selling fuel.

http://www.valvtect.com/marineFuelDiesel.asp

When Valvtec fuel is available, in my opinion it’s worth a few pennies more, sort of similar to top tier auto gas.
Worth reading if you have a car

https://www.consumerreports.org/car-...h-extra-price/

However I add Biobor JF to all my fuel, just as I did with turbine engine aircraft.

On edit, buy plenty of spare fuel filters, particularly if you ever travel beyond where your towing Insurence can come get you.
You may not need them, but they are I believe a good thing to have plenty of spares.

[slug]

Just cut a hole , clean out the tank then fit an inspection hatch

Many different hatches to choose from

https://wema.co.uk/products/flb-1-flange

Google it

[Quadrille in JB]

Since I cut a hole for my water level gauge I have been constantly plagued with bits of plastic jamming up the gauge. When I added inspection/cleanout ports I melted the holes using a soldering gun with a line cutting tip.
Worked great with zero trash added to the tank.

[NorthCoastJoe]

You can get a 90degree tip for a pressure washer and go in through the fill or sender holes.

[GarthGregory]

I have a Beneteau 473 in Greece - I had the same problem about 5 x years ago - mine is a black Roto moulded tank - I have limited access into the tank via the sender unit and the fuel pick up point . I took the tank out on my own ( 235 Liters ) and used Petrol to rinse the inside and then used a ( very ) high pressure cleaner to clean the inside - a very easy process . The hardest part was getting it out and back - it fits into the cavity under the berth with millimeters to spare . I now keep the tank absolutely full over winter ( approx 9 months) and always now use a biocide . The tank has remained absolutely clean - I would be hesitant to cut a hatch into the tank and I certainly would not be happy without having a completely clean tank .Things always go wrong at the worst time - Good luck

[EmeraldCoastSailor]

following

[NYSail]

I have a plastic tank in my 423 with only sender access. I borrowed a friends portable fuel pump... added a long clear plastic tube and used it like a vacuum on the bottom of the tank and ran to a large drum with a filter funnel . All was good until I Brought the hose to the fuel pick-up where I found that there is a molded sump. Picked up a large amount of slop.

Also I never fill tank in winter...... store with at most quarter of a tank and have never had water in tank 20+ years (Long Island ny). My opinion is to use the fuel and not let it sit in tank and get old and let the racor 500 do its job. But obviously location and tank type makes a big difference.

Good luck!

[a64pilot]

If you have room for an access cover, they are in my opinion a good idea. Unfortunately I can’t get enough of the sole up without destruction to fit one, or I would have one.
In my case it would be only partially successful due to the baffles in the tank to prevent sloshing, also prevent access to all parts of the tank from one hole, I believe I would need two, if placed correctly two access covers could access three compartments.

However in the past on my Brother’s Sportfisherman we have used a professional fuel polisher to great success, they have a LARGE pump that pumps a lot of fuel and a pressure washer wand to pressure wash the interior of the tank and in this ones case the filter was refillable and he used paper towels as the filter medium, the filter itself was about the size of a kitchen trash can.
It may have been special filter media that was on a roll like paper towels, I don’t know.

If fuel tank access is restricted this is one of the few cases that I will pay someone to do it, just because I don’t have the proper tools and I don’t believe you can rent them either.