Cutting out after cold start

[David Mutch]

Hi guys. Sorry to keep offloading my BMC woes on you. This is a small issue, but I want to nip it in the bud and make sure it isn't indicative of a bigger issue/doesn't lead to one. When my starter actually decides to crank, the engine will fire up with ease, even on the coldest mornings. Hardly ever actually needs pre-heating with glow plugs (although I tend to do this anyway, as I somehow feel it's kinder to the engine - I have no grounds for this assertion!) Recently, though, she's developed a habit of dying a few seconds after starting, unless some revs are kept on. This seems to be more likely to happen the day after a long hard run, as though the she was aching from the previous day's exertions! She will then start up again just fine and run smooth - no fuss and no bleeding required. I suspect this might have something to do with the injector pump, as she's never been quite the same since I had the pump refurbished. For one thing, I don't seem to be able to get the idle as low as before, and I'm pretty sure there's a spring missing from near the throttle arm (sorry I can't be more specific, as I can't remember exactly what the setup looked like before it went away for servicing). I was also wondering whether this could have something to do with the 'anti stall'? Any thoughts? Thanks!

[Flyboy]

To me it sounds like a lift pump problem & the the fuel is draining back overnight. Try it with a full tank of fuel & see if it makes any difference.

[Tony Brooks]

The missing spring was possibly off the stop lever.

If the stop does not fully return it reduces the MAXIMUM revs so it is unlikely to be that.

 

A maladjusted anti-stall "valve" can prevent you lowering the revs so check the adjustment as per the manual but it should not give these symptoms unless the idle is far too low and the "valve" is also maladjusted to allow the governor valve to move too fat to the no fuel position.

 

I assume that you do start the engine with at least some revs on it.

 

 

Are you sure all the previous problems have been cured?

 

 

 

 

 

[David Mutch]

To me it sounds like a lift pump problem & the the fuel is draining back overnight. Try it with a full tank of fuel & see if it makes any difference.

Thanks. I also suspected the lift pump was a possibility. I'll give that a go, as the tank probably isn't too full at the moment.

[David Mutch]

 

 

The missing spring was possibly off the stop lever.

If the stop does not fully return it reduces the MAXIMUM revs so it is unlikely to be that.

 

A maladjusted anti-stall "valve" can prevent you lowering the revs so check the adjustment as per the manual but it should not give these symptoms unless the idle is far too low and the "valve" is also maladjusted to allow the governor valve to move too fat to the no fuel position.

 

I assume that you do start the engine with at least some revs on it.

 

 

Are you sure all the previous problems have been cured?

 

 

 

 

 

I have set the idle as low as it can go, due to the problem with high tick over, so could be the problem. I Start with about half throttle, then back to idle when it fires. If you mean, have I solved all my engine issues, then no! But if you mean did the pump refurb cure the problem with the pump, then it did. Was leaking a considerable amount of diesel before it was sent off!

[Mikexx]

When the pump was fitted to the engine, was the anti-stall device adjusted?

 

As Tony has said the combination of a maladjusted anti-stall device and the tickover stop set too low would cause erratic idling.

 

The procedure I followed was to set the tickover by the "throttle" stop and adjust the anti-stall bolt until it affected tickover and unscrewed 2 flats. There is a more elaborate method as per:

http://www.asap-supplies.com/media/faq/131000-bmc-1.5-manual.pdf

on page 6 / M3

[David Mutch]

When the pump was fitted to the engine, was the anti-stall device adjusted?

 

As Tony has said the combination of a maladjusted anti-stall device and the tickover stop set too low would cause erratic idling.

 

The procedure I followed was to set the tickover by the "throttle" stop and adjust the anti-stall bolt until it affected tickover and unscrewed 2 flats. There is a more elaborate method as per:

http://www.asap-supplies.com/media/faq/131000-bmc-1.5-manual.pdf

on page 6 / M3

Thanks. I understand the anti-stall is the nut under the bleed screw on the top of the pump. Is this correct, as the pictures in the manual aren't too clear? Is it just a case of turning the thing one way or the other to change the governed speed? I haven't touched it until now, as I've heard a lot of horror stories about them shearing off!

[Tony Brooks]

 

Thanks. I understand the anti-stall is the nut under the bleed screw on the top of the pump. Is this correct, as the pictures in the manual aren't too clear? Is it just a case of turning the thing one way or the other to change the governed speed? I haven't touched it until now, as I've heard a lot of horror stories about them shearing off!

 

Yes, its the hexagon the bleed screw fits into. It is unlikely to sheer off or pull the insert out of the pump as long as you deal with its locknut properly and do not try any "gorilla" type loosening or tightening.

 

You change the governed speed by altering the stop screw by the throttle lever. Do not get mixed up with the maximum speed screw, the pump people should have hidden this one under and aluminium "can thing".

 

make sure the throttle cable is not preventing the lever returning to slow idle, better still do the adjustments with the cable off the pump lever.

 

By all means play with the anti-stall adjustment but in the end follow the proper instructions for setting it.

 

[David Mutch]

Yes, its the hexagon the bleed screw fits into. It is unlikely to sheer off or pull the insert out of the pump as long as you deal with its locknut properly and do not try any "gorilla" type loosening or tightening.

 

You change the governed speed by altering the stop screw by the throttle lever. Do not get mixed up with the maximum speed screw, the pump people should have hidden this one under and aluminium "can thing".

 

make sure the throttle cable is not preventing the lever returning to slow idle, better still do the adjustments with the cable off the pump lever.

 

By all means play with the anti-stall adjustment but in the end follow the proper instructions for setting it.

 

Thanks Tony. That's reassuring. Only problem with following the manual is the lack of a rev counter. Guess I will have to try and play it by ear! Edited August 19, 2016 by David Mutch

[Tony Brooks]

Somewhere in this site there are instructions for converting a cheap bicycle computer into a rev counter.

 

Look here http://www.canalworld.net/forums/index.php?showtopic=6647

Edited August 19, 2016 by Tony Brooks

[Flyboy]

Thanks Tony. That's reassuring. Only problem with following the manual is the lack of a rev counter. Guess I will have to try and play it by ear!

Something like this might be useful.

http://www.ebay.co.uk/itm/Noncontact-Tach-Tool-RPM-Handheld-Digital-Photo-Laser-Tachometer-Meter-Tester-UK-/141210169483?hash=item20e0c8308b:g:jjcAAMXQfvlSjsuc

[Mikexx]

Something like this might be useful.

http://www.ebay.co.uk/itm/Noncontact-Tach-Tool-RPM-Handheld-Digital-Photo-Laser-Tachometer-Meter-Tester-UK-/141210169483?hash=item20e0c8308b:g:jjcAAMXQfvlSjsuc

 

Thanks for the heads up to the source.

 

Just bought one as I don't trust my current tacho.

 

There are other sellers for the same item that are cheaper in the UK, or cheaper still if you don't mind waiting for delivery from China!

[Flyboy]

 

Thanks for the heads up to the source.

 

Just bought one as I don't trust my current tacho.

 

There are other sellers for the same item that are cheaper in the UK, or cheaper still if you don't mind waiting for delivery from China!

Yes there are cheaper ones but are plus postage so can work out dearer.

[Mikexx]

Hong Kong for £7.14 including postage

http://www.ebay.co.uk/itm/High-Quality-Automatic-Digital-Laser-Photo-Tachometer-NonContact-RPM-Tach-Tester-/131320109646

 

or the item I've just purchased for £8.29 including postage:

http://www.ebay.co.uk/itm/Digital-LCD-Laser-Photo-Tachometer-RPM-Tachometer-Non-Contact-Measuring-Tool-C3-/222078995586

 

Impressive value for money.

 

Before I saw your post I was starting to wonder how I might glue a magnet to the flywheel as per:

http://www.canalworld.net/forums/index.php?showtopic=6647

[David Mutch]

Thanks all. Will think about rigging something up, although I have been considering adding a proper rev/engine hours counter recently in any case

[Gordon Munk]

I would say it is fairly normal for an old engine to need a few extra revs whilst warming up

[David Mutch]

I would say it is fairly normal for an old engine to need a few extra revs whilst warming up

Not for my old engine!

[David Mutch]

Right. I hadn't looked into this further until today, as I hadn't had an opportunity to fill the diesel tank, and wanted to try this easy test first. Last night, however, with the engine ticking over at normal operating temperature, the idle speed began to drop, getting to a near stall by the time I got outside and cut the engine. I suspected a fuel problem, perhaps sucking up dirt or water from the bottom of the tank, as it was running low. So, today I extracted the dregs from the bottom of the tank, expecting all manner of sludge to come out, but all I got was near perfectly clean diesel (a small bit of sediment, and the tiniest amount of water, but nothing alarming, which surprised me after not having cleaned it out in four years.) I changed the fuel filter a few days ago, and that was clean, as was the gauze in the top of the lift pump. So, I refilled the tank with diesel (strained through an old T-shirt to catch any sediment, started her up, and she ran perfectly. Better throttle response than I've had in a while too. I haven't repeated the results yet, but I take it this indicates a weak lift pump. Any way to check this, or any easy servicing that can be done (other than cleaning the gauze)? Any other ideas? Thanks.

[Tony Dunkley]

Lift pumps do get 'tired' after long periods of service. The diaphragm stretches and wrinkles, and the two one-way valves wear and cease to seat and seal properly which reduces the pump's output pressure and volume.

 

Repair kits comprising new diaphragms and valves etc. are obtainable from fuel injection engineers.

[David Mutch]

Lift pumps do get 'tired' after long periods of service. The diaphragm stretches and wrinkles, and the two one-way valves wear and cease to seat and seal properly which reduces the pump's output pressure and volume.

 

Repair kits comprising new diaphragms and valves etc. are obtainable from fuel injection engineers.

Thanks Tony. Also, the pump didn't feel quite right when I was bleeding the system after changing the fuel filter the other day. Seemed to have less resistance than usual, although it still seemed to move enough fuel. I guess a service couldn't hurt, as I haven't done it before, and I doubt the previous owner did either.

[Tony Brooks]

Thanks Tony. Also, the pump didn't feel quite right when I was bleeding the system after changing the fuel filter the other day. Seemed to have less resistance than usual, although it still seemed to move enough fuel. I guess a service couldn't hurt, as I haven't done it before, and I doubt the previous owner did either.

 

But remember that if the engine stops with pump drive eccentric at or close to "full lift" the priming leaver will have a lot of slack and only deliver a small amount of fuel per stroke. If you find this turn the engine over about 1 turn so the pump lever is on the back of the eccentric.

 

Apart from the diaphragm the pump springs can break or go weak or the operating lever wear.

 

The later pumps had their valves fitted by staking (putting dents in the body) and those are hard to change the valves and get them to seal. If you are unsure I would suggest a new pump.

 

When refitting, whichever you do take great care to get the operating leaver on the correct side of the camshaft. You sort of slide the "hooky bit" up against the inside of the engine block.

[David Mutch]

 

But remember that if the engine stops with pump drive eccentric at or close to "full lift" the priming leaver will have a lot of slack and only deliver a small amount of fuel per stroke. If you find this turn the engine over about 1 turn so the pump lever is on the back of the eccentric.

 

Apart from the diaphragm the pump springs can break or go weak or the operating lever wear.

 

The later pumps had their valves fitted by staking (putting dents in the body) and those are hard to change the valves and get them to seal. If you are unsure I would suggest a new pump.

 

When refitting, whichever you do take great care to get the operating leaver on the correct side of the camshaft. You sort of slide the "hooky bit" up against the inside of the engine block.

Thanks Tony. I'm not quite sure what you mean. Does the "hooky bit" hook under the camshaft and get pushed down, or lie on top of it and get pushed up? I assume the latter. Is that right? I don't imagine the pump is a 'later' one. I don't mind risking a tenner on attempting a repair, rather than binning the whole thing, so long as a botched job isn't going to cause any further harm. Edited September 2, 2016 by David Mutch

[Tony Brooks]

Thanks Tony. I'm not quite sure what you mean. Does the "hooky bit" hook under the camshaft and get pushed down, or lie on top of it and get pushed up? I assume the latter. Is that right? I don't imagine the pump is a 'later' one. I don't mind risking a tenner on attempting a repair, rather than binning the whole thing, so long as a botched job isn't going to cause any further harm.

 

From memory the lever has to sit on top of the eccentric but it is all too easy to hook it underneath. When that is done a sensible person will find they can not get the pump flush against the block but the less sensible try to pull it in with the nuts and bend something.

 

If the valves are held in with a screw plate then by all means change them. If they are staked (came in around 1980 ish) then my advice would be to just change the diaphragm.

 

Remember that you need to pull the diaphragm down before tightening the body screws. If you do not you may tear the diaphragm when it gets pulled down.

 

Edited to correct some misspelt words I missed (screw plate, diaphragm down).

Edited September 2, 2016 by Tony Brooks

[David Mutch]

Thanks once again Tony. If our paths ever cross on the waterways one of these days, I'd say I owe you a pint or two!

[Mikexx]

My boat had the same symptoms where when the fuel level got below a certain level all ceased to function. The fuel pump lever was stiff and wouldn't return to allow any length of stroke.

 

Rather than messing with any repair I got one of these:

http://www.ebay.co.uk/itm/BMC-Leyland-Sherpa-Diesel-Lift-Pump-HFP176-7971139-/331945084717

 

As Tony has said, make sure the lever sits on top of the cam. There will be some force from the internal spring holding the pump away from the block. If not then its been fitted under. It's pretty obvious once you know.