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Ascertaining fuel quality.


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(My first post in a while!)

 

For a number of reasons, (Covid being high amongst them), both our boats have stood unused and unloved for far too long.

 

Trying to get things back on track, one boat has issues that the engine will still start without too much hassle, but having done so, it immediately dies - we are talking no more than 5 seconds of actual running.

 

Fuel contamination, (possibly the dreaded bug?), seems an early thing to rule out.  The fuel in both tanks looks visually quite clear, but I have not yet tried taking samples from low down.  (This is an historic boat, so we are talking tanks with a capacity well in excess of 500 litres, with probably some 300 litres of fuel present - a lot to deal with if it is contaminated).

 

So what can I do to assess the quality of the fuel, please?  Are the kits that allow you to test for the bug going to give me an accurate view?  If not, what should I be doing please?

 

The engine is a Lister HA2, and it is fed directly from the main tanks - there is no separate header tank involved

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If the 5 seconds running you do get sounds normal, I would be thinking the fuel is OK, but maybe there is a blocked fuel line or an air leak on the suction side of the lift pump.

Have you checked the filters are clear?

Maybe rig up a temporary gravity feed tank above the engine. If it then runs OK that would tend to confirm either an air leak or a blockage in the fuel filter or fuel line.

Edited by David Mack
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When I had the bug the fuel filter was rammed with junk, I didn't confirm it in any way but it looked like the various photos on the Internet, I also used a pela pump to syphon out a few litres and poured it in a clear bottle and left it to settle, this showed a scary amount of water plus very cloudy diesel.

I cured it with further siphoning and dosing with marine 16, plus very regular filter changes.

Now yearly siphoning to check and dosing with marine 16 and all is good

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1 minute ago, tree monkey said:

When I had the bug the fuel filter was rammed with junk

 

 

Yes, I think after dipping the tank (if possible) that's where I'd be looking next - assuming the problem is fuel-related.

 

I don't think 2 years is that long, but if you've got the bug, you've got the bug...

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37 minutes ago, tree monkey said:

When I had the bug the fuel filter was rammed with junk, I didn't confirm it in any way but it looked like the various photos on the Internet, I also used a pela pump to syphon out a few litres and poured it in a clear bottle and left it to settle, this showed a scary amount of water plus very cloudy diesel.

I cured it with further siphoning and dosing with marine 16, plus very regular filter changes.

Now yearly siphoning to check and dosing with marine 16 and all is good

 

 

I agree with Munk. Never mind testing kits, start off by drawing a sample of several litres of fuel from the bottom of the tank, put it in a clear container and look through it. The "quality" of what you drew off will be obvious!

 

 

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Just now, Tracy D'arth said:

If it only runs for 5 seconds it not fuel bug, its fuel non delivery.

 

 

True, which is why Alan is wanting to test for something which commonly causes fuel non delivery, by my reading of his OP

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Water in the fuel also seems possible but in my experience it starts off causing random stopping. Alan's seems to stop reliably every time after five seconds, so a blocked fuel supply seems probable. Diesel bug would be the fave candidate I'd say, given the circumstances and assuming the engine was running fine when last used two years ago.

 

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2 hours ago, David Mack said:

If the 5 seconds running you do get sounds normal, I would be thinking the fuel is OK, but maybe there is a blocked fuel line or an air leak on the suction side of the lift pump.

Have you checked the filters are clear?

Maybe rig up a temporary gravity feed tank above the engine. If it then runs OK that would tend to confirm either an air leak or a blockage in the fuel filter or fuel line.

 

Yes, my mind was already heading in this direction , if I can't quickly pinpoint the issue by other means.

 

2 hours ago, Tony Brooks said:

The Marine 16 people do or did supply test kits to allow you to test your fuel for the amount of bug present, but it takes a while in a warm place to incubate the test strip. maybe give them a ring.

 

Yes, I've seen info on this, though it wasn't obvious how reliable the result might be.

 

2 hours ago, StephenA said:

If you manually operate the fuel pump does it pump fuel?


Well there's the thing.  The movement on the lift pump lever seemed possibly a lot less than I remember.  It could however have stopped at the point the engine is operating the pump, which, in my experience of other diesels, means lever movement is restricted.  The battery was flattened, so I couldn't turn the engine over (no hand start on this HA2).

 

2 hours ago, tree monkey said:

When I had the bug the fuel filter was rammed with junk, I didn't confirm it in any way but it looked like the various photos on the Internet, I also used a pela pump to syphon out a few litres and poured it in a clear bottle and left it to settle, this showed a scary amount of water plus very cloudy diesel.

I cured it with further siphoning and dosing with marine 16, plus very regular filter changes.

Now yearly siphoning to check and dosing with marine 16 and all is good

 

Again I am thinking in this direction, but the diesel tanks are both the full length of the engine room, and not easy to siphon from a low point.

 

1 hour ago, MtB said:

I agree with Munk. Never mind testing kits, start off by drawing a sample of several litres of fuel from the bottom of the tank, put it in a clear container and look through it. The "quality" of what you drew off will be obvious!

 

Samples taken higher up in the tank looked clear to me

 

1 hour ago, Tracy D'arth said:

If it only runs for 5 seconds it not fuel bug, its fuel non delivery.


Yes, you would think so.

 

But I can't work out why it starts at all.  If the flow is impeded or blocked, I would expect it to be reluctant to start at all.
 

1 hour ago, MtB said:

Water in the fuel also seems possible but in my experience it starts off causing random stopping. Alan's seems to stop reliably every time after five seconds, so a blocked fuel supply seems probable. Diesel bug would be the fave candidate I'd say, given the circumstances and assuming the engine was running fine when last used two years ago.


I can't say "reliably every time", as the battery was in poor enough sate on latest visit for only one attempt.

I now have a shiny new charger sitting here at home, but as the battery is the one that was failing when we first acquired the boat, (possibly 10 years-ish ago) it seems optimistic that it can be returned to good health.  Hence I have ordered up a replacement from Tayna.

We are hoping to be at the boats this weekend, so hopefully a well charged battery will aid the investigations.

Edited by alan_fincher
Typos
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3 minutes ago, alan_fincher said:

Samples taken higher up in the tank looked clear to me

 

 

Meaningless. 

 

You need to take a sample at the same level in the tank as the lift pump draws from, i.e. nearly at the bottom. 

 

 

5 minutes ago, alan_fincher said:

But I can't work out why it starts at all.  If the flow is impeded or blocked, I would expect it to be reluctant to start at all.

 

 

Because after a rest, some fuel creeps through the restriction and eventually relieves the fuel vacuum that stopped the engine.

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Our engine was doing similar last year when the fuel pump was on its way out and wasn't feeding fuel sufficiently to keep the engine running so it would fire up and then cut out almost immediately.

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17 minutes ago, alan_fincher said:

I can't say "reliably every time", as the battery was in poor enough sate on latest visit for only one attempt.

 

Surely any self-respecting boater would have a solar panel array to stop this happening!

:giggles:

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47 minutes ago, alan_fincher said:

Yes, I've seen info on this, though it wasn't obvious how reliable the result might be.

 

They sent me a test and from what I can gather it is a pretty standard procedure. You take a sample of the fuel, add a buffering fluid, put a "test strip" into it., transfer the strip to another container and incubate it for a few days. Then compare the microbial spots on the strip with a printed card  to estimate the number of bugs.  My concern was how possible it was for contamination from whatever you used to take the sample of from the fuel filter drain where they suggested you could sample from.

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3 hours ago, alan_fincher said:

Well there's the thing.  The movement on the lift pump lever seemed possibly a lot less than I remember.  It could however have stopped at the point the engine is operating the pump, which, in my experience of other diesels, means lever movement is restricted.  The battery was flattened, so I couldn't turn the engine over (no hand start on this HA2).

Can you not turn it over half a turn by pushing on the flywheel with the decompressors lifted?
That should be enough to rotate the cam so that there is some free movement in the lift pump actuating lever.

 

 

3 hours ago, alan_fincher said:

Again I am thinking in this direction, but the diesel tanks are both the full length of the engine room, and not easy to siphon from a low point.

If you drop a tube directly down to the bottom of the tank below the filler that should be close enough to the draw off level.

Edited by David Mack
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15 hours ago, MtB said:

 

Water in the fuel also seems possible but in my experience it starts off causing random stopping. Alan's seems to stop reliably every time after five seconds, so a blocked fuel supply seems probable. Diesel bug would be the fave candidate I'd say, given the circumstances and assuming the engine was running fine when last used two years ago.

 

 

When I had 30 litres of water in the bottom of the fuel tank of my last shareboat, it first became apparent as a lack of power followed by the engine stopping and refusing to start just as I tried to exit Watford bottom lock.

 

An engineer with a Pela pump removed the water, added diesel and primed the system to restore normal service.

 

Turned out the boatyard we were at, had never heard of using water finding paste and removing water from the bottom of external, above ground tanks annually. Turned out that their bulk tank was nearly half full of water! 😱

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4 minutes ago, cuthound said:

Turned out that their bulk tank was nearly half full of water! 😱

Meaning that the value of the stored fuel was half what they thought (unless they can sell all that water to unsuspecting boaters at diesel prices).

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Just now, David Mack said:

Meaning that the value of the stored fuel was half what they thought (unless they can sell all that water to unsuspecting boaters at diesel prices).

 

That is exactly what they were doing. It had previously Ben a yard which operated a hire fleet, but the new owners sold off the fleet and preferred to make their money by offering moorings to private owners and shareboats.

 

Initially they hadn't a clue (they repainted our shareboat in winter, but it was too long for their heated tunnel so they had to repaint the back half again as the paint bloomed and blistered) but I understand they are a bit better now.

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If you really want a proper test kit, use a Microb Monitor2, which was developed by Air BP and ECHA.  The problem is that each test costs about £50, so unless you have some very good friends from the old days, probably a non-starter!

Chris G

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We recently had issues with our new Eberspacher water heater. I used our oil extractor to take samples from various levels of the fuel tank. From the bottom was definitely water based diesel and a few black ‘blobs’ of muck. From the top was nice clear red diesel. From the middle was, unsurprisingly, something in between.

 

As a footnote. It seems some gunk from our aged radiators had blocked the water pump. Now ‘presently’ working fine, at the moment! Fingers crossed. 

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An update....

 

We have come up to the boats hopefully better equipped than when I first tried to look briefly at this issue.

 

What we have includes...

 

New battery

New battery charger

Pela pump

Marine16 diesel bug test kit

Replacement fuel filter **

 

** Unfortunately this is no good.  HAs normally use the metal cased type that fits between a top and base.  Sadly the HA2 in question (an ex industrial engine) uses a paper element which goes inside a permanent "can".

 

So far I know...

 

The fuel passing through the lift pump looks clean

The manual operating lever on the lift pump doesn't feel very "convincing" - a significant amount of force still produces less movement than I might expect.

Like last time (with a new battery), it started straight away, but unlike last time continued to run at probably less than tick-over for maybe a whole minute.  Winding the speed up and down however produced no discernable difference.  Just briefly it sounded like it might pick up some speed, but the died.
I haven't been able to reproduce this since.
I've not tried sampling the tanks yet.

 

Any ideas, please?

 

 

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Bar the engine over half a turn to get the lift pump cam in a different position and try the lift pump again. If you undo the fuel inlet connection on the injector pump, and then operate the lift pump do you get a plentiful supply of fuel? If you do then you know the lift pump is operating and the filter can pass enough fuel. If you get next to nothing, that would suggest a fuel blockage somewhere.

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1 hour ago, David Mack said:

Bar the engine over half a turn to get the lift pump cam in a different position and try the lift pump again. If you undo the fuel inlet connection on the injector pump, and then operate the lift pump do you get a plentiful supply of fuel? If you do then you know the lift pump is operating and the filter can pass enough fuel. If you get next to nothing, that would suggest a fuel blockage somewhere.

 

I would suggest roughly a full turn unless the HA drives its fuel pump from the crankshaft, which I doubt. Half  a turn on the crankshaft is a quarter turn on the camshaft so the pump lever/plunger would still be on a raised part of the camshaft eccentric.

 

Edited to add: if the pump lever is on the eccentric it should have a lot of slack movement and not much firm movement on the priming lever. Something similar will happen if the pump builds up fuel pressure, so the pressure holds the diaphragm down (assuming a diaphragm pump). First open a pipe fitting or a bleed screw AFTER the pump and see how much fuel flows and if you suddenly get less slack and more firm movement on the priming lever. If not then turn the engine one full turn. Decompressors if you have them set to decompress and use a large screwdriver as a lever in the flywheel teeth. If you can't access the teeth then try this. Ring spanner or ratchet on the alternator pulley nut. Start to turn and note which bit of drive belt goes slack. Push that run firmly down or in and that will usually allow the engine to turn. Note: this is not best practice but is practical.

Edited by Tony Brooks
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Another update, (after much head scratching)...

 

I found it hard to get consistent behaviour, and apart from one attempt that again saw it running for up to a minute, but only on a "slow tickover" with no response to the speed wheel, it fell back to a point where it didn't start at all.

 

Attempts to manually pump fuel seemed to be working when I broke the connection between pump and filter, but when reconnected to the filter the delivery seemed to stop.  Opening up the filter there was a very little black powdery matter in the bottom of the housing, but really not very much at all.  The fuel looked clean, and there was nothing visibly trapped in the paper element.

There are several joints, as well as a cut off tap, in the feed from tank to lift pump, but I tried giving all an extra tightening with a spanner, and none seemed loose or likely to be drawing in air, Eventually, with persistence I was able to hand pump fuel until it was coming out of the bleed screws on the filter.

 

The engine then started but again with only a "slow tickover", and no response on the speed wheel, and ran this way for over a minute.  Then, when it seemed it might stall, it slowly started to speed up.  After about a minute or two of erratic running, it was behaving fairly normally, and the speed could finally controlled on the speed wheel.  I left it ticking over for an hour or more. Leaving it an hour so, (but while still quite hot), KI was able to start immediately with no problem whatsoever.

 

So it seems there was some kind of contamination somewhere, which hopefully has now self cleared.

The question now is am I prepared to take it for a spin down the cut - or is there a danger it might die on me when several miles from the mooring.

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