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3LW will not always pick the revs up


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When I start the engine and leave it running for a few minutes, when I open the throttle, the revs will only pick up very, very slowly then suddenly burst into life. This happens whether the engine is hot or cold, in gear or in neutral. If I keep "blipping" the throttle, it will respond straight away.

 

I have tried running run with the fuel cap off in case of a blocked breather and also stopping and immediately restarting does not clear the problem. A new lift pump was fitted last year (for an unrelated problem) and made no difference. (Note, there is no day tank)

 

All the filters have been changed, fuel and injector pipes on the engine cleaned out and the main fuel lines cleaned out. The fuel is not contaminated.

 

There is no discernible pattern to this behaviour and has done it on and off for a couple of years. Sometimes it can go for months running fine.

 

As you can imagine, stopping can be a worry!

 

Secondly, can anyone advise as to how to adjust the tickover speed.

 

Any advise gratefully received.

 

Many thanks.

 

Tony

 

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Do you have a big alternator? Does this tend to happen when the batteries need a charge? Narrowboat installations often use big pulleys to drive the alternator so that it charges at low engine revs. If this is overdone, you can end up with the alternator taking all the engine power at idle and as the engine starts to pick up, the charge rate picks up also and absorbs that power that should be accelerating the engine: it takes ages for the engine to speed up past the point where the alternator is maxed out, and the extra power can be used to accelerate the engine.

 

MP.

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Thanks for your replies.

 

Dove: Spring is still in place.

 

Chris: I guess it is something we will both have to live with then?

 

MP: Good point, the engine does have 2 big alternators driven by a big pulley. However, the last time it was reluctant to rev up (yesterday), the boat had just been on a land line for a month and I know the batteries were fully charged. I will disconnect the alternators next time it happens though and let you know the outcome.

 

Thanks again.

 

Tony

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Chris: I guess it is something we will both have to live with then?

 

 

 

I don't know, i'm only just getting to grips with this engine. To me it's almost as if it wants to be in a boat that has an engineer - a lot more complicated than my National or my Lister.

 

I hadn't really thought about it much, it was your post that made me think, "hang on, that's what mine does"

 

I don't think the alternator thing is it.

 

The other odd thing my engine does - it's a steady as a rock all the time but if it's on idle out of gear for a while, every so often (once every couple of minutes) the revs will slowly pick up, not hugely but noticeably, over 2 or 3 seconds and then go back down to normal idle again. It's not been used much for a year so I put this down to "needs a blast" and it seems to be lessening. under load it's absolutely steady.

 

But now you've posted I'm going to see if I quantify this pickup problem a bit more. To be honest I thought that's the way it was and that's it but now you've got me thinking. Though not having instant reverse is a bit disturbing.

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Chris,

 

As my fuel tank is situated lower and someway from the engine, it has been suggested to me that the slow pick up could be temporary fuel starvation and a small electric pump in the fuel line before the lift pump could possibly overcome this problem. (The engine never had this problem for the first 2 years of ownership). A cheaper alternative than fitting a day tank.

 

Tony

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Mine has a day tank, right above the fuel filter. But I won't try and confuse your thread any more, I want to really quantify it first and make sure it is the same thing. I know it takes a while to pick up but I don't know how intermittent it is.

 

I just kind of assume it's slow to pick up but then sometimes it surprises me.

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I seem to have got a handle on mine. Not completely because boating took preference to engine diagnostics. If left in idle for any length of time (not sure how long) it will take a while to pick up. If it's just briefly in idle (less than a minute or so) then it has no problem roaring.

 

This seems reasonably consistent (except I don't know exactly how long or if that is a consistent length of time).

 

It must be quite a short time because I remember, last year, taking out a wooden post because reverse didn't pick up fast enough when I had been idling in to a mooring.

 

it will stall (always !) if I start the engine, do some stuff then put it into gear without first taking the revs up out of gear. It then seems to pick up slowly when restarted.

 

Which would imply definitely not fuel starvation (there would be plenty available if in idle for a while) but could be a governor fault or 'stickiness'.

 

I will ask my engineer to investigate (in my dreams)

 

I hope this helps Tony.

Edited by Chris Pink
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Hi Guys

 

Have you tried lubricating the fuel pump quadrents, this is done either through a 2 BA screw fitted in the quadrant cover or by removeing the cover held on by 2 nuts (3/16 spanner)

Cover is the one behind the fuel pump levers

Gardner reccomend that 30cc of engine oil every 12.000 miles.Keeping the internals lubricated is essential if the slider bar tension spring has been adjusted to lower the tickover speed

Can make quite a difference.

 

Innconsistent tickover speed can be caused by an incorrent adjusted slider bar buffer setting, try screwing it out 1/4" turn to se if it makes any difference.

The buffer is to make sure that the engine does not stall when running down to tickover, when the throttle is shut down quickly, it gives the slider bar a bit of help enableing the govener to do its job

 

Steve.

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Chris,

 

Thanks for the update.

 

My engine usually displays the problem straight away if it is going to play up on that particular day.

 

It doesn't stall when I put it into gear. I have run the engine today and is OK! No doubt tomorrow it will play up again. I would be interested in your engineers verdict.

 

Steve,

 

The injection unit looks slightly different to the unit in the manual I have. I have a pull out cold start on the "trigger box" if that is the correct name? I cannot see a 2BA screw or a cover behind the fuel pump levers.

 

Did Gardner fit different types of units I wonder? My engine came out of a Smiths crane originally.

 

Thanks again,

 

Tony

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Sounds like sticky something then. So Steve's idea is a good un. I haven't identified the quadrant cover yet. There is a cover behind the priming levers (Steve's fuel pump levers?) I was about to post a picture but then I thought I might as well take the 3 3/16" screws out and have a look for anything quadrant like.

 

I haven't managed to appoint an engineer yet, whenever I show them the crew's quarters and tell them the pay, they laugh for some reason and leave.

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Sounds like sticky something then. So Steve's idea is a good un. I haven't identified the quadrant cover yet. There is a cover behind the priming levers (Steve's fuel pump levers?) I was about to post a picture but then I thought I might as well take the 3 3/16" screws out and have a look for anything quadrant like.

 

I haven't managed to appoint an engineer yet, whenever I show them the crew's quarters and tell them the pay, they laugh for some reason and leave.

Here's a pump with the cover removed (pinched from another thread)

 

assembled.jpg?i=1134049774

 

Tim

Edited by Timleech
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SImilar but different.

 

I assume steve's post means the two nuts arrowed. If so does the whole cold start mechanism come away too without removing anything else? It's one whole casting. Theres also two slot head screws (arrowed top left and bottom right) the bottom right looks like it might match Steve's description.

 

Sorry about the quality of the picture, there's not much light in there.

 

gallery_4525_993_235428.jpg

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SImilar but different.

 

I assume steve's post means the two nuts arrowed. If so does the whole cold start mechanism come away too without removing anything else? It's one whole casting. Theres also two slot head screws (arrowed top left and bottom right) the bottom right looks like it might match Steve's description.

 

Sorry about the quality of the picture, there's not much light in there.

 

gallery_4525_993_235428.jpg

Mine is also similar but the cold start arrangement is different.

 

I am wary about undoing the 2 nuts as indicated on your photo as mine have a fine wire through each stud with a wax seal attached but, if you look further down, there are 3 bolts that appear to be securing a plate. On mine it has 2 bolts securing a plate but again with a securing wire through them both. Is this the plate I wonder? If so, do you think it is OK to just lubricate the quadrants by squirting oil from an oil can, as I cannot see any way of getting any oil into the chamber from above?

 

Probably like you, I am worried about doing more harm than good!

 

I also don't have the slot head screws as indicated.

 

Thanks again.

 

Tony

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I removed the screw top left (it's actually behind the protusion in the casting that you can see. It had a pin on the end of the screw (about 5/8" long all told) and squirted dollop oil in and oiled the rack at the other end, touch wood, it's been behaving today. But again boating had taken priority so I'm not 100% sure.

 

Though I had a couple of hours at lunchtime while a family overturned their cruiser on the cill (mur de chute) of a staircase just outside Carcassonne. I wish the British canals were run by VNF. They were brilliant.

 

I can't get a good purchase on the screw bottom right without taking an engine cover out so I left that.

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The other odd thing my engine does - it's a steady as a rock all the time but if it's on idle out of gear for a while, every so often (once every couple of minutes) the revs will slowly pick up, not hugely but noticeably, over 2 or 3 seconds and then go back down to normal idle again. It's not been used much for a year so I put this down to "needs a blast" and it seems to be lessening. under load it's absolutely steady.

 

Just to put my twopennyworth in, my 2LW does exactly the same. This rise in revs is so slight and otherwise the engine performance is so good, i have no intention of adjusting anything.

 

George ex nb Alton retired

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I did put this down to not having been used for a while. Mine is not particularly slight, although it doesn't run away with itself. I kinda figure it all linked as in my non-engineering way it all seems to be 'sticky governor' and lubrication is probably the key.

 

The 2BA screw instruction is in my 6LX manual. But the pump is different to mine.

 

gallery_4525_993_112118.jpg


There's a hole showing on this diagram that has a screw in it on mine that is just a hole in this.

 

I have oiled through the screw, as I say, in the top of the fuel control box and hopefully that's done the trick.

 

I have a plethora of information about 6LX which I am beginning to feel is pretty useless to my 4LW.

 

I have an instruction manual for the 4LW what I could really do with is the parts list. (and, of course, the workshop manual to give to my imaginary engineer)

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SImilar but different.

 

I assume steve's post means the two nuts arrowed. If so does the whole cold start mechanism come away too without removing anything else? It's one whole casting.

 

 

Yes it does. The pump that Tim nicked the photo of ( :) ) has a cold start mechanism (on a 2L2).

 

Having said that, there's bugger all for you to fiddle with in there.

 

However - try running with that cover off and see if your engine picks up cleanly now. The 'cold start' is done by overriding the overfuel stop. Experimentally, I tried the 2L2 without the cold start cover and it solved the 'not picking up' problem completely. It seems that the governor wants to open the rack just a little more than the stop will allow. There are a range of pawls for the cold start, perhaps a different one is needed

 

Richard

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InjectionPump_zps5e644043.jpg

 

This is the pump in question. I have not seen one like this on any other 3LW. I have removed the brass plug which is on the cold start and put in a small amount of engine oil.

 

I have also found the 2BA screw and removed to try and put some oil in. Unfortunately, it is a very long screw (about 1 & 1/2 inches long) and I am not sure how much, if any, oil I managed to get in using my oil can as most of it ran out behind the casing. I need a can with a very small spout, almost a syringe. I will try again when I get a suitable oiler. However, the engine has run perfectly today.

 

 

Tony

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Tony

Page from spare manual showing pump tops

The Nuts labeled 8,/9/10 (Stud washer and nut) are the ones that I was refereing to as per your photograph

The screw label 12 is the 2BA screw (IF FITTED) Not all covers have it.

In the spare parts list it actually called the Fuel Control Box, and only shows one type, but the maintenance manual refers to one without the cold start device for automotive applications.

I have a number of LW manuals and spares lists and they show considerable difference's down the years.(usually discontinued or modified parts)

If the screw is absent then the only way to lubricate the quadrents is by either removing the cover completely or carefully pulling it back just enough to get the end of an oil can in.

It the cover labeled 36 is in place then it will need to be removed also.

When refitting the cover it may be necessary to manually move the slider bar backwards and forwards to get the trigger stop back into place (part of the cover assembly)

The advantage to removing the cover is that you can also apply oil directly to the end bearings on the slider bar and manually move the bar in and out to get some oil into the bearings

It the wire seals are still on the pump then there is no problen in just snipping the wire to remove them, they are fitted when the pump is callibrated to prevent anyone altering the max fuel setting. a necessicity for road engines where the Ministry of Transport could easily check at the roadside.

 

The slotted head screws which are shown just above the 12 annotation should not be disturbed , they are the alingment pins for the pump elements.

 

fuel%20pump%20page.png

Edited by Split Pin
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InjectionPump_zps5e644043.jpg

 

This is the pump in question. I have not seen one like this on any other 3LW. I have removed the brass plug which is on the cold start and put in a small amount of engine oil.

 

I have also found the 2BA screw and removed to try and put some oil in. Unfortunately, it is a very long screw (about 1 & 1/2 inches long) and I am not sure how much, if any, oil I managed to get in using my oil can as most of it ran out behind the casing. I need a can with a very small spout, almost a syringe. I will try again when I get a suitable oiler. However, the engine has run perfectly today.

 

 

Tony

Tony

I think that yours may have been fitted with a remote cold start device,

I think you said it came out of a crane so it may have been difficut to reach.

Mine also came out of a Smiths crane and was Gardner Engine no 11 acording to the original crane plate, it is the same as the illustration.

I will have a look through the other books that I have to see if I can find your type shown anywhere

 

Do you know when your engine was built, mine was 1952 engine no 91628

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