Diesel Bug and Marine 16 treatment - is it working?

[dylan winter]

Picking up from a previous thread

I bought a Fisher 25 with pretty bad diesel bug - it had not really been used for 7 years

Stainless steel 40 gallon tank -  the owner said that the tank had been treated and kept full - but I doubt that he had used more than  half a tank in the past seven years.

While I was there the yard JCB stopped running because of diesel bug.

I put a whole 100ml  of marine 16 in

https://www.marine16.co.uk/fuel-treatments/dbt

I replaced the filter before starting to bring her home - there were some black crystals across the top of the filter - it looked like rust flakes - but it is a stainless tank with copper pipes. 

No worries, I had put an outboard bracket on the boat and slapped the tohatsu long shaft 6hp on the back - that will shove a centaur along at 4.5 knots so I would expect it to get me 4Knots on the fisher,

I headed south through a choppy north sea - the volvo engine went very well for four days

day four  - overnight the engine stopped half way across the wash  - after I would  guess 40 hours during the sea trials and first bit of the journey

no worries I had the Tohatsu on the back

I brought the boat back to the mooring under sail and outboard and changed the filter

There was some gelatinous black stuff the consistency of toothpaste on the filter top - ideal for blocking pipes

The engine ran well on the flat water estuary here for another 30 hours and then stopped - mid estuary

no worries.... I had the Tohatsu on the back

I changed filter and saw some generalised greyish stuff across the filter

The engine then ran fine for another 20 hours

I was planning a short winter juant out into the north sea so I replaced the filter just to find out what it looked like

this is what it looked like on Friday - this one was running  well

On monday I headed out past the deben bar - I had intended to go north to the Ore which is marvelous for birdwatching..... but there was more power and more easterly in the wind than predicted

the Ore bar is bad in any easterly and the shingle is always moving - the bouys are only a guide -  so I headed south to the walton backwaters

into the teeth of a south easterly gusting 25. No sails to add stability

the north sea was really choppy and confused and the Fisher is tubby, draws 1m, has a lot of weight up high and is only 25 feet long. She was rolling like a goodun. The tank was being given a top notch shaking in every dimension  as the boat was powering through the messy water at 5 knots

After an hour of this the revs started to drop away, then come back,  then drop away. I started the outboard but left the main engine on low revs.   It would not run at high revs for more than one minute.  Once afely  across the Felixtowe ship channel I could ease up and the water flattened out. The erratic revs continued for half an hour, but the tank was still getting a bit of a shake.

I got into walton channel, picked up a mooring  mainly under outboard and  left the engine on tickover - primarily  to charge the batteries. . It was running fine, so I experimented, I  slowly increaed the revs at five minute intervals. Occasionally the revs would  drop right back down, so I came back to the revs it was happy at again. After half an hour of this the engine would run at any revs I chose. It seems that the blockage had cleared. 

This morning the engine started no probs -  I brought the boat back home - maybe two hours of choppy water motor- sailing  five knots through disturbed water - less rolling than the day before.The engine did not miss a beat.

Incidentally, the taylor heater has its own header tank (fed from the main tank)  and water/gunge trap.  The first time I ran the heater the gunge trap was half full of black crud, I removed that and now there is a tiny layer in the bottom, it seems quite fine and fluffy and seems to be dissolving as fuel passes through to the taylor heater.

I think that the Marine 16 is reducing the gelatinous  diesel bug crud initially to a free flowing black flakey material and then dissolving that down to a general discolouration in the fuel which they claim is burnt in the engine - you can see that some it has clung to the first filer but there is much less of it on the second.

I am lucky in that my boat is short enough to have an outboard on the back and sails  so the main engine stopping is not mission critical.  I also have a north sea for some extreme and randomised tank shaking procedures.  If by the spring this problem has not resolved istelf then I will have to  bite the bullet and either cut a hatch to access the tank or remove both the engine and the tank to clean the lot out.

So far, I am optimistric and if Marine 16 can not only control but destroy the crud then that is a wonderful thing - worth the price if it works.

 Dylan

 

[TwoLegged]

Dylan, I am not a mechanic, and I am averse to more than minor tinkering.

But I would be worried by your approach, because it seems to me that you will never actually know what the state of your tank really is.  It may be that the crud in your tank is like a bar of soap nailed just above the waterline of the bath, where the degree dissolved soap is a roughly linear function of the amount that it gets splashed.  Or it may be that the crud consists of a number of well-adhered lumps which are inert until dislodged, but dislodged by extreme action.

If the latter case applies, then a crud-free period may mean that the crud has all gone ... or alternatively it may mean that only the low-hanging fruit has been dislodged so far, and that much more crud remains to be dislodged after further wave action.

Your current use case makes the outboard a viable backup, but if you resume your exploration of Scotland, then there will be many cases where the outboard is an inadequate backup, making a main engine backup dangerous.  I'd have thought that creating an access hatch would be a better solution, a non-huge job which would allow you forever more to get a  definitive answer about the state of the tank.

 

[Israel Hands]

Can you access the tank to get a siphon hose into it?  Short of draining the tank, that's what I would do to inspect the fuel. I wouldn't feel confident till I got a look at a decent sample of fuel in a clean container.  Start by siphoning around a couple of points on the tank bottom, raise up a bit and repeat...

(Edit: I guess you don't have a removable tank intake like the one on my SS tank?  If not, cut a hatch.)

 

[Raz'r]

Can you access the tank to get a siphon hose into it?  Short of draining the tank, that's what I would do to inspect the fuel. I wouldn't feel confident till I got a look at a decent sample of fuel in a clean container.  Start by siphoning around a couple of points on the tank bottom, raise up a bit and repeat...

Actually, he could do that via the supply line to the engine.

 

[Israel Hands]

Actually, he could do that via the supply line to the engine.

Yes, it would just siphon right at the bottom of the tank where the supply line starts, but that's better than nothing.  My supply line is bolted into a cutout on the top of the tank. That's where I've removed and test-siphoned when necessary.

 

[SASSAFRASS]

Growth will typically stick to the walls and bottom of the tank, unless horrible then can be all over.  The additives will kill it but you usually have to mechanically remove, IE hose and flush or go bobbing around with a slack tank...  Even if you have swapped or turned over the fuel you can still get periods like above after getting rolled around a bit till it's all worked out.

 

[Ishmael]

Anyone used a cheap inspection camera to look inside a tank? I see there is one for $30 locally. Might be worth it even if it never worked again.

 

[longy]

Almost certainly there is a fuel tank level sender, those have about a 2" hole. Enuff to get a camera (lots of them that attach to phones) into the tank, and easy to re-secure  sensor.

 

[Steam Flyer]

If a diesel will ring up full (or near full) power, then revs drop, then a few minutes later, will ring up power again, it's more likely to be an air leak in the fuel line that crud in the filter IMHO.

Having those filter canisters you have to cut open to see what's in it is also hurting the ability to diagnose. What I'm seeing in the recent pic is not the kind of power-robbing filter clog that I'm familiar with. Generally filters that are blocking flow will have something like coffee grounds, or chocolate pudding, gumming it up.

But I agree that an outboard is a poor back up. In high wind or chop it will simply not get the boat where you need to go. Fuel is also a PITA.

FB- Doug

 

[IStream]

Dylan, I went to the Marine 16 website and see no claim that their bug treatment gets rid of the dead bugs, only that it kills them. I don't doubt your observation that things are getting better but I do question your implicit assumption that the tank is actually getting clean. 

I strongly second the motion that you, at the very least, get a camera into the tank but I will continue to suggest that you install an access port in the cockpit sole above the inspection port for the tank. It only hurts once. After you do it and deal with whatever may or may not be mucking up your tank, you'll put to rest all the lingering doubts you'll ever have about the condition of your fuel tank and, by extension, the reliability of your motor.

 

[py26129]

I had similar symptoms to Dylan,s for a few years. They were intermittent until the grunge clogged the pick up tube screen in the tank. I siphoned the tank dry and was amazed at the amount of crud suspended in the fuel.  Thankfully the walls of the tank were clean.  I worked through the fuel sender opening.  There was plenty of room for the siphon hose and a cheap proctologist's camera.  The camera was no worse for wear and the engine runs like a too since.  We were hauled out when I emptied the tank and got pretty good suction from the syphon

 

[dylan winter]

Almost certainly there is a fuel tank level sender, those have about a 2" hole. Enuff to get a camera (lots of them that attach to phones) into the tank, and easy to re-secure  sensor.

no hole for a fuel sender, it does not have any guage.  At some stagbe a non standard stainless steel tank was fitted

it is a big one and there is a 3 inch gap between it and the cockpit floor.

There is always the hatch option, but I will see if Marine 16 does as it says on the tin. I have time and the north sea.

 

[dylan winter]

If a diesel will ring up full (or near full) power, then revs drop, then a few minutes later, will ring up power again, it's more likely to be an air leak in the fuel line that crud in the filter IMHO.

Having those filter canisters you have to cut open to see what's in it is also hurting the ability to diagnose. What I'm seeing in the recent pic is not the kind of power-robbing filter clog that I'm familiar with. Generally filters that are blocking flow will have something like coffee grounds, or chocolate pudding, gumming it up.

But I agree that an outboard is a poor back up. In high wind or chop it will simply not get the boat where you need to go. Fuel is also a PITA.

FB- Doug

it spent the past two hgours running smoothly - I am not sure how that would square with  an air leak. Iassume they do not tend to come and go.   I expect to be clocking up bout ten or 12 hours motoring each week through the winter....... if by March I am not free of it then I will have to bring the boatb ashore.  I did siphon the tank out when I bought the boat, the fuel looked clear - all 30 gallons of it, but I did not know how much of the tank I accessed - the fuel looked clear .... but the boat had not been used at sea for 7 years.

 

[dylan winter]

If a diesel will ring up full (or near full) power, then revs drop, then a few minutes later, will ring up power again, it's more likely to be an air leak in the fuel line that crud in the filter IMHO.

Having those filter canisters you have to cut open to see what's in it is also hurting the ability to diagnose. What I'm seeing in the recent pic is not the kind of power-robbing filter clog that I'm familiar with. Generally filters that are blocking flow will have something like coffee grounds, or chocolate pudding, gumming it up.

But I agree that an outboard is a poor back up. In high wind or chop it will simply not get the boat where you need to go. Fuel is also a PITA.

FB- Doug

the last one did not stop the flow - I removed that one before leaving the estuary when the engine was still running after several hours of lat water sailing and motoring inside the bar.

 

[dylan winter]

Dylan, I went to the Marine 16 website and see no claim that their bug treatment gets rid of the dead bugs, only that it kills them. I don't doubt your observation that things are getting better but I do question your implicit assumption that the tank is actually getting clean. 

I strongly second the motion that you, at the very least, get a camera into the tank but I will continue to suggest that you install an access port in the cockpit sole above the inspection port for the tank. It only hurts once. After you do it and deal with whatever may or may not be mucking up your tank, you'll put to rest all the lingering doubts you'll ever have about the condition of your fuel tank and, by extension, the reliability of your motor.

you make a good point

now I can not see the reference to it clearing up rather than just  preventing  problem

perhaps my strategy has a fatal flaw

I will keep this thread posted as new information emerges

D

 

[dylan winter]

this is a review from PBO in the UK

https://www.pbo.co.uk/gear/12-diesel-bug-treatments-tested-43353

it suggests that the biocides break the cells down enough to alloow them to pass through a ten micron filter - and then presumably be burned in the engine

To see how easily the fuel would pass through the filter we agitated the sample and filtered it twice at 10 microns. The first pass removed inorganic and particulate matter, leaving the treated fuel. We timed the second pass through a clean filter to show how easily the treated fuel will pass through it. This gives an insight into the type of contamination left in the fuel – if it is the colonies, emulsions and thready compounds typically found in cases of diesel bug they will quickly accumulate, blocking the filter and slowing the passage of fuel, while other less tenacious contamination will pass through. Hence samples which passed slowly through the second filter would be likely to block the filter entirely over time.

the taylor heater has a separate header tank fed from the filter. When I got the boat the previous owner said that he had never used the Taylor heater

initially the fuel in the taylor heater water trap site glass looked like this

I removed the crud and the the Taylor did gunge up and stop twice.  Initally gelatinous stuff in the burner inlet, then the second time flakey light stuff merely slwoing the flow

after two tanks of fuel pumped into the header tank and run through the heater it looked more like this

I emptied that out and there is no more crud accumulating - now on my fourth header tank of fuel - only 1 gallon or so.

I am hoping that the same is happening in the main tank.  I have a glass water trap under the filter - that is clear

Dylan

 

[Ajax]

With no local or remote fuel gauge or sight glass, how do you determine your fuel level? Do you use a dip stick?

 

[Steam Flyer]

this is a review from PBO in the UK

https://www.pbo.co.uk/gear/12-diesel-bug-treatments-tested-43353

it suggests that the biocides break the cells down enough to alloow them to pass through a ten micron filter - and then presumably be burned in the engine

To see how easily the fuel would pass through the filter we agitated the sample and filtered it twice at 10 microns. The first pass removed inorganic and particulate matter, leaving the treated fuel. We timed the second pass through a clean filter to show how easily the treated fuel will pass through it. This gives an insight into the type of contamination left in the fuel – if it is the colonies, emulsions and thready compounds typically found in cases of diesel bug they will quickly accumulate, blocking the filter and slowing the passage of fuel, while other less tenacious contamination will pass through. Hence samples which passed slowly through the second filter would be likely to block the filter entirely over time.

the taylor heater has a separate header tank fed from the filter. When I got the boat the previous owner said that he had never used the Taylor heater

initially the fuel in the taylor heater water trap site glass looked like this

I removed the crud and the the Taylor did gunge up and stop twice.  Initally gelatinous stuff in the burner inlet, then the second time flakey light stuff merely slwoing the flow

after two tanks of fuel pumped into the header tank and run through the heater it looked more like this

I emptied that out and there is no more crud accumulating - now on my fourth header tank of fuel - only 1 gallon or so.

I am hoping that the same is happening in the main tank.  I have a glass water trap under the filter - that is clear

Dylan

Owww

You definitely have lots of crud.

How much fuel is your tank? Is it possible to drain the tank, into another container(s), flush the tank out at least a little, then put the fuel back in from the top and avoid the crud settling in the bottom? This won't eliminate all of it, but should get the worst. Start with a fresh filter and see what comes thru.

Air leaks, yes they come & go. Air will suck thru a leak that diesel fuel will not drip thru. If you have old copper fuel lines, they have probably become brittle with age (like my knees) and good to replace. You can find industrial fuel hose cheaper than marine, made to the same specs (in the same factory), you already know about going to farm stores instead of yachting stores! But if this is part of your problem, it would probably recur more often.  That you've made a power run recently with no problem is a good sign.

FB- Doug

 

[dylan winter]

With no local or remote fuel gauge or sight glass, how do you determine your fuel level? Do you use a dip stick?

At the moment not even that

I know how much is in there only when it is brim full

An untenable situation but one that has been tolerated by the three previous owners who have had it since the stainless steel 40 gallon tank was installed

This is a problem yet to be solved.

I can put a plastic site tube in the fuel line close to the tap     that would help me guess but would be in breach of safety regulations

The electrics continue to provide many hours of exploration, contemplation, entertainment and puzzlement. The approaches to problem solving and electrical trial and error of five men are revealed in the torturous labyrinths of wires, chokkie connectors and gaffer tape that lurk beneath the console and under the ceiling liner

D