access to fuel tank on LM 32

[johnty]

Hi all,
I have recently acquired a 1984 LM32 which needed the injectors & diesel pump sorting on the Bukh 36.
It appears that there is considerable diesel contamination which will need to be cleaned before starting the motor & I wonder if anyone has any advice as to how this should be done please?
The tank is GRP but I'm not sure if there are any access points to be able to get a look in or be able to use to facilitate cleaning through?
Has anyone any experience with this please?
Many thanks
John

[oceandancer]

Hi Johnty,
I have no specific info on the LM32 but I have an LM27 and have regularly cleaned the tank via the round hole where the fuel level sender is fitted. On the LM27 this is a VDO unit mounted on a round plate and the hole into the tank is about 60 or 70 mm diameter. You should have something similar on your boat.

With the unit removed - you will have to disconnect it, unscrew it and wrestle with it a bit to get the float out of the tank, you will be able to look down into the tank with a torch to see the yuk at the bottom of the tank which collects at the very lowest point just by the tube drawing off the fuel. WATER ALSO COLLECTS HERE

Cleaning is relatively simple IF you have a vacuum oil extractor, the round sort you pump up by hand. Just fit a long piece of tube to the business end, a length of 15mm copper tube will do or some similar tube. You then insert the tube into the tank and position it close to the fuel extraction pipe. Using the oil extractor draw off a quantity of fuel. If doing this for the first time I would advise at least 2 or 3 litres. You can monitor where the gunge is located using a torch and move the extractor tube about accordingly in order to remove it.
If you decant the extracted fuel into a clear container you will be able to see how much water you had at the bottom of the tank.
Water will naturally form in the tank during the winter months due to condensation. It used to be that owners filled the tank at the start of winter to try to avoid this but the prohibitive cost of fuel and the relatively large fuel tanks in the LMs preclude this somewhat.

The other cause of gunge is the dreaded diesel bug which forms a black slime. Now that ethanol is being added to all diesel fuel, even red, this bug is more prevalent. I use a diesel biocide to control the bug and clean my tank every year.

If you have had problems with your injection pump then you will also need to change all the fuel filters.  All owners should check the bowl at the bottom of the 1st fuel filter every time the boat is used in order to detect problems early BEFORE contaminated fuel is drawn into the engine.

Hope this helps.

Happy sucking!

Mick

[johnty]

Thanks for that Mick.
Very helpful. I'm sure that the tank arrangements are similar so will follow your advice.
Don't go away though!
Johnty

[Brian & Glenda]

I have an 1983 LM32. Access to the fuel tank is gained by opening the hinged floorboard under the helmsman's feet. At the bottom of that cupboard is a wooden lid that opens up to reveal the top of the fuel tank. Directly below that wooden cover is a decently sized fiberglass plate access panel through the top of the fuel tank. That panel is held in place with several screws. There is a gasket between the top of the tank and the access panel. The fuel gauge float switch, the fuel pickup tube, along with the fuel return tube are all attached to that panel. You can see straight to the bottom of the tank from there. The bottom of the tank is still along way down though!

I had troubles with my fuel gauge once, so I affixed a 3/4" diameter irrigation fitting with threaded cap to that fiberglass panel, so I could dip the tank. Works great... Although I did buy a new fuel level sending unit / float ... I still dip the tank with every fueling.

I think Mick's suggestions will work well from there.

Have fun!

Brian.

[johnty]

Many thanks for that Brian. Will get onto it. I like your idea of the dipping stick. Have you any experience in actually cleaning the tank given the depth? It seems that mine has never had any sort of clean-out & given the level of contamination I'm sure that my tank could function as a vegetable patch! Nice surprise for me as the new owner! Thanks again. Johnty

[Brian & Glenda]

No I have never had to clean the tank, or the fuel. We bought our boat four years ago, and it came with a clean tank. Thankfully, it has stayed that way ever since!

I did poke my head in there when I replaced the fuel level sending unit shortly after buying the boat. If I recall correctly there are two full height but perforated baffle plates in the tank, on either side of the sending unit; so it may be very challenging if not impossible to reach the entire bottom of the tank. Instead, you may have to figure out how to slosh some fuel around while extracting it, to flush all of the contaminants out of the tank.

(My fresh water tank, which is identical in size and design to the fuel tank, does not have any baffles. I have reached it's extremities to clean it... but had to use a stick to reach the far corners. It is much easier to access than the fuel tank access panel, as you don't have to reach over the walls of, then down into the bottom of the storage compartment beneath the helmsman's feet. Also, the access into the freshwater tank is larger than the access into the fuel tank. The fresh water tank access can be found under a wooden panel in the floor of the cupboard just below the galley sink. Once the wooden lid is removed, you'll see a fiberglass lid on the top of the tank that is held in place by two nuts on fixed bolts, that hold a retaining crossbar that spans the width of the opening. The fresh water tank level sending unit is attached to that fiberglass cover. A sponge gasket between the lid and the tank keeps the water in the tank when the water is sloshing in the tank. I've had to change that sending unit too!)

I think that Mick's idea should work well to remove any minor amounts of contamination, but if there is a high level of contamination and/or you have a large volume of fuel in your tank, you may wish to get someone in to 'polish' your fuel. There are a couple of companies that offer this service here on Vancouver Island, B.C., Canada, but I have no idea who may perform that service in Britain. They simply bring a portable tank alongside / dockside and pump your fuel through large filters to remove all of the contaminants before pumping it back into your tank. My brother had that done for his boat. (not an LM) Not cheap, but cheaper than replacing all of the fuel, and the motor certainly ran better once the fuel flowed freely!

Like Mick, I also add a biocide to my fuel each time I add any fuel. I also add a fuel conditioner. Not sure exactly what that does, but the mechanic who looked at the engine before I bought the boat, recommended I use these two products every time I fuel; so I do. I don't have the brand names of these products on hand right now ... they're on the boat and I'm not at the moment, but I could look into that next time I'm down. I don't know if you'd have the same brands available in Britain or not.

Don't forget to change those fuel filters to new one's once you've got the fuel all cleaned up!

It's a bit of a story how I came to have them; but I have two Racor water separator/fuel filters with see-through bowls and drain plugs in line before the fuel gets to the filter affixed to the engine. I check the fuel cleanliness before every engine start, simply by looking through the fuel in the Racor filter bowls. The drain plugs allow me to easily drain any debris or water from the bowls. The first Racor has a 30 micron element and the second Racor has a 10 micron element. Thus, the standard filter that is attached to the engine - 2 micron - serves as a tertiary filter. I rarely find any debris or water, but I still change all three filter elements every year, and (touch wood!) have never had any problems with fuel.

(At the time I bought the boat, I had asked the aforementioned mechanic to change the single primary fuel filter to a dual primary such that I could switch from one primary to the other primary quickly if the first filter ever got plugged. He didn't do that, instead he chained the two new filters together as described above. I haven't yet re-plumbed them to get what I was looking for. Some engine manuals (my brother's Universal) say not to chain three filters together, but the current arrangement doesn't seem to cause any problems for my Bukh DV36.)

Hope that helps,

Cheers,
Brian.

[johnty]

Hi Brian,
Thanks for all that. Very interesting but I still have the problem of what appears to be a badly contaminated tank & no obvious way to clean the whole thing given the two baffle plates which run fore & aft on either side of the limited access hatch. These plates have a bevel cut out of each corner to allow fuel to move through but they make it impossible to get to the rest of the tank.
I have just had to have the diesel pump & injectors done & drained 175L out of the tank which was full of gunk & water. I have cleaned the accessible part but reluctant to use the engine without attending to the rest of the tank. I agree about the use of biocides etc but they won't do much for existing contamination & the Racor filters are great but fear that they may clog up on a very regular basis!
Has anybody out there had this problem? Are there any answers as to how to access the inside of the whole fuel tank?
We are now even at a stage of taking out the engine, removing the fuel take & replacing it with an aluminium one but this seems to be overkill just to clean a fuel tank!
Big help needed please!
Johnty

[Brian & Glenda]

If I were in your shoes, I'd consider using a garden type sprayer with some clean fuel in it to flow fuel over, or 'pressure wash' the more difficult to reach portions; and then suck up that contaminated fuel using an oil extractor. The wand of the sprayer should be able to reach into each chamber of the tank. If it's bendable ... so much the better. Iterative flushing and removal in such a manner might get you to your end goal.

You could perhaps remove the nozzle from the sprayer for the first couple of flushes to see if simply flowing fuel over the contaminants could move them to a spot they could be removed. Perhaps tilt the boat to one side a few degrees to get the contaminants to one side of the tank, and to make the contaminated fuel easier to remove. If you need to use the nozzle on the sprayer, I'd put an in-line fuel filter on the sprayer's intake to avoid fighting contaminants plugging the nozzle.

You may choose to take a 1" or so hole saw to the baffles in strategic spots, to facilitate the spraying and removal. Big enough to accomplish the goal, but not so big that fuel could freely slosh from one side to the other. Any sawdust will be removed with the other contaminants, and any that still remains would easily be caught in your primary filter.

It is very easy to change the filter in a Racor ... simply unscrew the T handle, and lift the filter element out. The elements are not very expensive.

Perhaps the duel primary filters I described above, is the way for you to go. Simply switch the fuel flow valve from the first primary to the alternate primary when the first gets plugged. No need to even turn the engine off to change filters.

Brian.

[oceandancer]

Hi Johnty,

I'm not sure where you are based but there is a firm in Port Solent called The Clean Diesel Company that carry out fuel polishing for £250 which is, I suppose, the sort of cost you would pay anywhere.

The fuel is filtered then centrifiged which is supposed to get rid of all the water which is required for the bug to thrive.

Regards

Mick

[chrismunson]

Have a pro clean the tank. Its not worth messing with all that crude! Also, do not unscrew the round sender plate - the nuts will go 'plink' into the tank. 1st close the fuel valve. Remove the fuel pickup, then the large fiberglass hatch into the tank, then the sender. When its all back together, run the engine at the dock for 20+ minutes to be sure the fuel line is free of air, or you'll stall at the worst possible time. All learned the hard way!

[jonsutton66]

May 30, 2018 0:53:46 GMT Brian & Glenda said:

I have an 1983 LM32. Access to the fuel tank is gained by opening the hinged floorboard under the helmsman's feet. At the bottom of that cupboard is a wooden lid that opens up to reveal the top of the fuel tank. Directly below that wooden cover is a decently sized fiberglass plate access panel through the top of the fuel tank. That panel is held in place with several screws. There is a gasket between the top of the tank and the access panel. The fuel gauge float switch, the fuel pickup tube, along with the fuel return tube are all attached to that panel. You can see straight to the bottom of the tank from there. The bottom of the tank is still along way down though!

I had troubles with my fuel gauge once, so I affixed a 3/4" diameter irrigation fitting with threaded cap to that fiberglass panel, so I could dip the tank. Works great... Although I did buy a new fuel level sending unit / float ... I still dip the tank with every fueling.

I think Mick's suggestions will work well from there.

Have fun!

Brian.

[jonsutton66]

Hi all.
I have recently taken ownership of an LM32 Argosy based in Wick Scotland.
I noticed a small amount of diesel under the engine. Checked all fuel lines & filters appear sound.
Whilst sailing the tank was full we had a good lean to port perhaps a bit much. Is there anyway fuel could come from tank into bildge. Interior breather or inspection plate.
Any ideas would be appreciated.
Regards
Jon Sutton

[Brian & Glenda]

If the oil spill is appearing within the supposedly waterproof fiberglass engine compartment, and not in the bilges outside the engine compartment, then the fuel must be coming from a leak within the engine compartment. (leak in fuel supply line, at pump connections, loose secondary filter, loose injector lines or injector?, fuel return line)

If there is also fuel outside the waterproof engine compartment, then it could be spilling from the top of the tank because of a leaky gasket on the fuel tank lid (access is from compartment under helmsman's feet, as noted above), or from the primary fuel filter (if outside the engine compartment, as on my LM32), or a leak in the supply or return lines, or their connections to the tank, or the tank level guage. (The lines and guage all go into the tank via the removable lid on top of the tank.)

The fuel could get from the outside of the waterproof engine compartment into the waterproof engine compartment via a loose connection at the combustion air inlet which is located low on the starboard side of the engine compartment, immediately adjacent the fuel tank; or if you have a fresh water cooled engine, through a loose connection where the coolant hoses exit the engine compartment housing and run aft to their anti-siphon valve which is located under the aft deck near the steering quadrant. These two openings are approx 4" in diameter and have hosing similar to a collapsible plastic dryer vent hose clamped to them, and those hose clamps may have become loose allowing water or fuel from outside the engine compartment into the engine compartment. If left loose, should the saildrive gasket ever leak, sea water could also get from within the engine compartment into boats main the bilge and potentially sink the boat if the water ingress is not noticed for a while, so these connections should be checked. (and perhaps a water level alarm installed, as Chris has noted in a separate post) But: I think you'd have to have quite a significant fuel leak outside the engine compartment for it to enter via those two means!

Hope you can find the leak! Good luck!

Cheers,
Brian.

[jonsutton66]

Thanks Brian for your advice. I am away for 3wks but have a friend look at her again in a days time.
I will pass on you're advice to him.
You have covered all of the things in a professional manner.
Thank you very much I will keep you in the loop of progress
Regards
Jon