Grotamar 82, Old Fuel, Blocked Filter

[CaptainBob]

Got what I think is about 200-300 litres of 3 year old diesel in my 600 litre tanks when I bought the boat last autumn. I promptly stuck in a shock dose of Grotamar 82 in and left it for the winter.

Tested on land before launch and all was fine. Intended to top up the tanks with fresh fuel asap.

On the way to the fuel station the engine suddenly without warning slowed and stopped, over about 20 heart-stopping seconds.

An uneventful "rescue" by the HM and a primary filter change, and we're back up and running again. Now with another 200 litres of fresh diesel on top of the old, as advised by the local engineers. And another 200ml of Grotamar in for good measure.

But I'm thinking that if the fuel blocked the last filter, won't it do the same to this new one? I have a spare now, just in case, but I'd rather avoid having to make an impromptu change.

I did "pela" some fuel out from the very bottom of both tanks to take a look and it was very dark like old fuel, with quite some "bits" in it. But it didn't seem to contain lots of water or "sludge".

Thoughts?

TY!

 

[wotayottie]

There is a limit as to how much water and crud can be dealt with by any treatment.

Personally I have my doubts about the treatments. I cleared my tank as best I could and have treated very litre put in since then bu I suspect I have again got the bug - engine speed varying as before.

Best thing you can do is to pump out the bottom layer of diesel in the tank. I did this with a portable electric drill and a rotary pump from wolf.

 

[Schuss39]

Suggest you have a search on the Nauticat USA group based on Yahoo. Quite a well known issue with old fuel left standing and muck in older fuel tanks. A fair number of posts over the last few months and possible solutions.

I assume both of your fuel tanks do not have inspection hatches either! I treated both my tanks with a heavy dose of Marine 16 and used a small fuel polisher to extract 200+ Lts into jerry cans. Then also pela'd out as much muck from the bottom of the tanks having removed the fuel gauage sender units to access the tanks. Refilled the tanks with the fuel via the polisher just to ensure there was no muck left.

You may wish to consider building in a fuel polisher system into your engine room which would allow you to circulate your fuel on a regular basis to extract any muck (see the Nauticat USA site for photos and diagrams plus old posts on YBW).

You could also fit a second primary fuel filter in parallel (with valves) with your current primary filter. This would allow you to quickly switch between them rather than changing filters on the go.....

 

[stevek]

grotamar

I suspect what has happened is that the grotamar has killed the diesel bug/biofilm in the tank which has then been drawn through the filter and blocked it. You can expect this to happen when using a shock dose. Replacing filters should resolve this but it will depend on how much bug there is. No biocide can remove diesel bug so the dead bugs have to go somewhere.

 

[Otter]

With so much fuel in there I would call in a mobile fuel polisher and get the lot "cleaned". Then clean your fuel tank and refill with the clean fuel. You have to ask how much peace of mind costs and knowing you have a tank with potentially a lot of sludge waiting to make its presence felt when you're in rough water and the contents get sloshed about - potentially just when you need the engine most.

 

[CaptainBob]

Thanks for all the suggestions. The parallel fuel filter with a changeover is such an obvious/good idea. TY.

Mobile fuel polisher - is there such a thing? Is there one in/around Dartmouth?

 

[Trundlebug]

Thanks for all the suggestions. The parallel fuel filter with a changeover is such an obvious/good idea. TY.

Mobile fuel polisher - is there such a thing? Is there one in/around Dartmouth?

Don't bother wasting your money on a mobile fuel polishing service.

For less than the cost of a one off mobile visit you can BUY all the gear you need and do it yourself. This is supposed to be the Practical Boat Owner forum, after all!

You may find my two threads useful in this respect, also addressing your point about a fuel filter changeover system.

http://www.ybw.com/forums/showthread.php?t=309724

http://www.ybw.com/forums/showthread.php?t=314108

 

[RobbieW]

Having put Grotamar in its probably too late to say that the Marine 16 Bug treatment product is supposed to break the bug up into pieces small enough to go through the filters and burn off in the engine.

I wa pretty sure I had bug in at least one tank and have used the Bug treatment for each fill since, something like 1500 litres over 3 years. The primary filter gets a fine dark residue in the bowl which is consistent with broken down bug but so far no actual blockage (now wheres that cross finger icon when you want it!)

 

[NOHOH]

The Trouble with Biocides.......

......is that they just produce a pile of dead bodies.......which essentially have the same effect as all the live bug bodies....ie they just block the system up......

Far better....IMHO ....to use an enzyme treatment such as Soltron.....which essentially...given time ...will dissolve anything organic in your tank and turn it into something that will go through the injectors and be burned (inorganic debris will of course have to be physically removed)...and put a stop to another one of these "growth industries"...namely `fuel polishing`.

Triple dose your tanks... then leave it for two or three weeks.....sample and see how successful the treatment has been...and if necessary ...dose it again.....

When you are finally clear of the stuff...just dose every time you fill up...

Touch wood...I`ve been doing this for quite a long time and don`t have any problems due to diesel bug