BMC Diesel engine won't start

[Mayflower]

Hi All,

 

Another newbie problem. Got a 1.5l BMC diesel engine. Last ran it in November. Then got caught by the big big freeze, during which it wouldn't start and I assumed it was just too cold and the diesel had turned to jelly. Last three times I've been to the boat (Jan and Feb) have tried to get it to start but it just won't catch. Even when the temperature was above zero.

 

I've got solar panels which re-charge the batteries between visits. I've been holding the heater button in for a good 2-3 minutes before first attempt, and then for 90 seconds or so before every further attempt. It seems almost to catch but never quite does. I've got a slightly leaky exhaust manifold and I get small clouds of whitish smoke from that - so I think I've got fuel reaching the cylinders (and coming out of the exhaust unburned).

 

People have said glib things like the glow-plugs need removing and cleaning and the injectors need cleaning but I'm not yet at the stage where I feel competent to take either of them out (too many rigid fuel lines involved!). Someone has suggested an aerosol tin of Eazy Start spray into the air intake. But I've heard people say this is a bad thing!

 

I guess I'm after finding someone who would come and look at it (for payment) but I don't really know where to start asking - or whether there are other things even a newbie should try first. But the longer I leave it the worse I expect it to get. I would like to be cruising at Easter, not fretting on what is turning into a house-boat!

 

Mayflower

 

PS and now I've read the 'are new boaters thicker than they used to be?' topic I feel the need to add that yes, I used to service my own (car) engines back in the day when you could actually get at anything but that was over 20 years ago and yes I'm probably being thick - but I'd rather ask for help first than break stuff and trhen ask for help afterwrads.

Edited March 10, 2010 by Mayflower

[RLWP]

First thing, I don't think you are thick. I'd ignore that thread, I am.

 

Second. Glow plugs are easy to work on as they don't interfere with the fuel system. You can do some simple checks with a cheap voltmeter to see if they are getting power without removing them, and perhaps some resistance checks without taking them out of the engine at all.

 

Does anyone know if a glowplug gets hot enough to be able to feel the warmth at the electrical terminal? If so, you may be able to do some tests without dismantling anything

 

Richard

[David Schweizer]

Hi All,

 

Another newbie problem. Got a 1.5l BMC diesel engine. Last ran it in November. Then got caught by the big big freeze, during which it wouldn't start and I assumed it was just too cold and the diesel had turned to jelly. Last three times I've been to the boat (Jan and Feb) have tried to get it to start but it just won't catch. Even when the temperature was above zero.

 

I've got solar panels which re-charge the batteries between visits. I've been holding the heater button in for a good 2-3 minutes before first attempt, and then for 90 seconds or so before every further attempt. It seems almost to catch but never quite does. I've got a slightly leaky exhaust manifold and I get small clouds of whitish smoke from that - so I think I've got fuel reaching the cylinders (and coming out of the exhaust unburned).

 

People have said glib things like the glow-plugs need removing and cleaning and the injectors need cleaning but I'm not yet at the stage where I feel competent to take either of them out (too many rigid fuel lines involved!). Someone has suggested an aerosol tin of Eazy Start spray into the air intake. But I've heard people say this is a bad thing!

 

I guess I'm after finding someone who would come and look at it (for payment) but I don't really know where to start asking - or whether there are other things even a newbie should try first. But the longer I leave it the worse I expect it to get. I would like to be cruising at Easter, not fretting on what is turning into a house-boat!

 

Mayflower

 

PS and now I've read the 'are new boaters thicker than they used to be?' topic I feel the need to add that yes, I used to service my own (car) engines back in the day when you could actually get at anything but that was over 20 years ago and yes I'm probably being thick - but I'd rather ask for help first than break stuff and trhen ask for help afterwrads.

First of all let me say that you are not the only person who has difficulty in starting a BMC 1.5 in cold weather, nor has being a "newbie" got anything to do with it, so dont beat yourself up. One of the well known problems with older BMC 1.5 engines is that they do not like starting in cold weather, especially after a long period of not being run. We have one in our boat which has done less than 800 hours since a complete re-buid and it is a pig to start in cold weather.

 

You are doing the right thing to allow a couple of minutes heater operation before attempting to start, but do you have the throttle well open? You will meet people who say that this is not necessary, don't listen to them, it is, and the official manual says so. When you hear the engine trying to catch, keep the stater going and waggle the throttle between quarter open and half open, I don't know why this helps but it does. Do not wind the engine for too much more than a minute, as this could overload the starter and will also flatten the battery, just repeat the whole operation again, it could take three or four attempts before the beast will fire up, and then it might only be reluctantly.

 

If your attempts contuinue to fail then there are several options, wait until the weather improves and the temperature has been well over freezing for quite a few days, the BMC responds much better in warmer weather, or investigate the glow plugs, but a word of warning, whilst this is a comparitively straight forward job, it is very easy to break the heater tip off (voice of experience) if you do not know how to remove them leave it to some one who does ( but watch them so thatyou can do it next time!), the whole job should not take more than a couple of hours at the most, so it will not cost a fortune. You do not say where the boat is located, I can recommend an excellent engineer based in Braunston if you are within a reasonable distance from there, but the BMC is a very common engine in boats so any decent marine engineer should be able to sort things out for you.

 

There is one other faint possibility for non staring, and that could be the dreaded diesel bug, which could block the injectors or the feed pipes. If this is the problem, the system will need flushing out and a new filter fitted, again not a difficult job and less than an hour for a competent engineer.

 

Hope this helps and Good luck.

Edited March 10, 2010 by David Schweizer

[GBBS]

Ok, if you are even trying to warm up the glow plugs for 2-3 minutes they are not working. If you can check the current they are drawing with a clamp meter. If not then a voltmeter will have to do. there should be 12v when in heat position if yes but still not hot then one or more glow plugs are dead. It is unusual for all of them to fail at once but even one will affect cold starting.

If you do not have a clamp meter, yes they will get hot enough to feel it and after 2-3 minutes the wires to them will also be glowing so a fair bet they are dead if cold.

If you do decide to remove them be careful, if they have not been out for a while they may stick and the ends snap off. Use a good quality socket or ring spanner and ease them out carefully, 1/2 turn out 1/4 turn back in again. when you replace them a smear of copper slip will help in future. now to start the engine in the mean time. Do not use easy start it damages engines and is a last resort. remove the air filter and aquire a blow torch. Turn over the engine and at the same time point the blow torch into the air inlet, you may need to keep it on for a few seconds after it fires until the revs pick up. New glow plugs are not expensive and your nearest motor factor should be able to source the from Durite. Also check that either the glow plug relay, if there is one, is working if not then check that the ignition switch is supplying power to them - a volt meter will suffice for this.

 

Dave

[PhilR]

Mayflower

 

Where are you in Cheshire?

[RobinJ]

Does anyone know if a glowplug gets hot enough to be able to feel the warmth at the electrical terminal? If so, you may be able to do some tests without dismantling anything

Yes, if the block is cold, you can easily detect the difference in heat on the 'nutty' bit.

 

Can only be two problems really.

1) Heat - Very cold any problems with heaters will stop firing!

2) Fuel - Bug and contamination not likely to spread while standing unless lots of water in fuel, more likely to be an air lock. Cold also shows up leaks as pipes shrink etc.

[Bones]

Yes, if the block is cold, you can easily detect the difference in heat on the 'nutty' bit.

 

Can only be two problems really.

1) Heat - Very cold any problems with heaters will stop firing!

2) Fuel - Bug and contamination not likely to spread while standing unless lots of water in fuel, more likely to be an air lock. Cold also shows up leaks as pipes shrink etc.

 

 

Or the stop switch not returned back in to its start position - check this manually (engine end!).

[stuart]

I'd second checking the stop switch/lever - after my friends boat's BMC engine was removed and then re-installed in a boat we accidentally wired the throttle to the engine stop lever! Spent a good hour trying to figure out why the engine would cut out when revved up!

[alan_fincher]

As others have said, you are not being thick, at all, and are saying the right kind of things.

 

The BMC "B series" in either 1500 or 1800 form makes a good narrowboat engine, and will be both reliable and durable if you get things right.

 

They do have their foibles, as other have said, and as I'm an 1800 man rather than a 1500, some of the most useful advice will probably come from owners of the latter, where starting often seems harder than with the later model.

 

Although just basically the same engine with differing bore sizes, other detail certainly differs. I believe all 1500s will usually use an old style glow plug where the "it can break off if not removed for a while" thing applies, so think twice before trying to remove IMO, as you can test some things without. Most, not all 1800s use a fatter later plug that normally doesn't suffer this issue, so question clearly any replacement plug you need to buy.

 

Even the most basic multimeters, (sub ten quid in Wilkos), usually have a DC amps range, of say up to 10 amps, so you can detach each heater plug connection in turn, and pass the 12 volts in via the multimeter (in series) set up to read on the high amps range. You usually need to plug test leads into different holes - on absolutely no account connect both leads across the 12 volts, positive and negative, when reading high amps, or you will have a small plastics fire - don't ask me how I know this! I don't recall figure for amps on a 1500 plug, (hopefully someone like Tony Brooks will tell us), but almost certainly vrery well less than 10 amps, and will fall slowly as plug heats correctly. Any that doesn't do broadly what the others do is probably cream crackered, and should be replace, but heed warnings, as it can be "head off" if it breaks.

 

Then got caught by the big big freeze, during which it wouldn't start and I assumed it was just too cold and the diesel had turned to jelly.

 

This worries me slightly - if you drew off diesel, was it just waxy, and if you do it know, is it free flowing and clear ? Unless you are sure of fuel quality, I'd not rule it out. When was filter last changed, please ?

 

If you do not have a clamp meter, yes they will get hot enough to feel it and after 2-3 minutes the wires to them will also be glowing so a fair bet they are dead if cold.

 

Personally I doubt that quite a bit. I'd be pretty confident a working 1500 plug draws less than 10 amps with a fully healthy battery, and wiring I have ever seen would carry than indefinitely without getting noticeably warm. Personally on my 1800, (which uses more power on the heaters, so should get hotter), I've never felt the ouside of the plug warm, but then I'd never run them for in excess of a minute either.

 

Our 1800 was always a good starter, even when it was apparently operating heavily coked up, and with cracks in the cylinder head, and some head gasket failure. Paradoxically, now the head has been replaced by a newly skimmed renovated one, and the gasket changed, although the engine is running sweeter, it has become harder to start. As the engineer broke the connector to one plug taking it from the old head, and had to buy new, he recommended changing all 4. I do wonder if the new ones, (presumably modern manufacture of an equivalent to whatever originally fitted, are quite as effective. Still starts OK, (white smoke always a feature!), but just not as well as when it was "shot"!

[FadeToScarlet]

Or the stop switch not returned back in to its start position - check this manually (engine end!).

 

I too have attempted a couple of times to start the engine with the stop pull out. It's one of those very simple mistakes that it's easy to make, and leads to many a "D'oh!" moment, but that's nicely easy to rectify too!

[alan_fincher]

To add to my previous post, my experience of failing to start our 1800, until batteries to knackered to try, related to "absolutely convinced I had fully bled the fuels system from tank to injectors", when in fact I had not.

 

If you know the fuel had "turned to jelly", you may have had something disconnected, and if you don't have the knack, (and I didn't) of bleeding, the bugger will not start come rain or high water. Tony Brooks has previously given excellent advice in other threads on "how to bleed a BMC", and on my last filter change it all wents heaps more smoothly.

 

Just because some fuel is getting throgh, don't assume it can't be fuel.

[Mayflower]

To add to my previous post, my experience of failing to start our 1800, until batteries to knackered to try, related to "absolutely convinced I had fully bled the fuels system from tank to injectors", when in fact I had not.

 

If you know the fuel had "turned to jelly", you may have had something disconnected, and if you don't have the knack, (and I didn't) of bleeding, the bugger will not start come rain or high water. Tony Brooks has previously given excellent advice in other threads on "how to bleed a BMC", and on my last filter change it all wents heaps more smoothly.

 

Just because some fuel is getting throgh, don't assume it can't be fuel.

 

 

Wow- thanks folks! I'll read and digest.

 

Regarding the fuel/jelly thing - sorry - that was clearly misleading. I have no evidence that the fuel is jelly - it was just that after we'd tried to start it at -6 degrees someone had said that at that temp the fuel wouldn't actually be frozen but it would be heading towards being jelly - as in reluctant to be pumped and even more reluctant to turn to spray and ignite.

 

I can do the metering (already got DVMs - will check one will go up to 10A).

We haven't bled the fuel lines, nor checked for airlocks.

Certainly too timid/cautious to take the glowplugs out.

It *feels* like the time we tried to start it with the stop widget not fully down - but we have pressed that as fully down as we can! Hoping against all hope we haven't got a crack in something awful - we don't know for certain that the antifreeze was at the correct strength (like I said - the early onset of the winter (and late onset of brain cells) caught us out.

 

 

 

Now I need to read the rest of your messages in proper detail - back later (supposed to be working at this time of day :-) )

[Bones]

Wow- thanks folks! I'll read and digest.

 

Regarding the fuel/jelly thing - sorry - that was clearly misleading. I have no evidence that the fuel is jelly - it was just that after we'd tried to start it at -6 degrees someone had said that at that temp the fuel wouldn't actually be frozen but it would be heading towards being jelly - as in reluctant to be pumped and even more reluctant to turn to spray and ignite.

 

I can do the metering (already got DVMs - will check one will go up to 10A).

We haven't bled the fuel lines, nor checked for airlocks.

Certainly too timid/cautious to take the glowplugs out.

It *feels* like the time we tried to start it with the stop widget not fully down - but we have pressed that as fully down as we can! Hoping against all hope we haven't got a crack in something awful - we don't know for certain that the antifreeze was at the correct strength (like I said - the early onset of the winter (and late onset of brain cells) caught us out.

 

 

 

Now I need to read the rest of your messages in proper detail - back later (supposed to be working at this time of day :-) )

 

check it at the engine end - the actual lever... don't trust the cable.

Edited March 11, 2010 by Bones

[Sir Nibble]

Wow- thanks folks! I'll read and digest.

 

 

I can do the metering (already got DVMs - will check one will go up to 10A).

I think you will blow the fuse in the meter. The cold resistance in a glow plug is much less than at working temperature. Just disconnect the plugs one at a time and shove a 12V supply from battery +ve on each one in turn, if you get a little spark then current is being drawn and the thing is most likely ok.

[David Schweizer]

Wow- thanks folks! I'll read and digest.

 

Regarding the fuel/jelly thing - sorry - that was clearly misleading. I have no evidence that the fuel is jelly - it was just that after we'd tried to start it at -6 degrees someone had said that at that temp the fuel wouldn't actually be frozen but it would be heading towards being jelly - as in reluctant to be pumped and even more reluctant to turn to spray and ignite.

 

I can do the metering (already got DVMs - will check one will go up to 10A).

We haven't bled the fuel lines, nor checked for airlocks.

Certainly too timid/cautious to take the glowplugs out.

It *feels* like the time we tried to start it with the stop widget not fully down - but we have pressed that as fully down as we can! Hoping against all hope we haven't got a crack in something awful - we don't know for certain that the antifreeze was at the correct strength (like I said - the early onset of the winter (and late onset of brain cells) caught us out.

 

 

 

Now I need to read the rest of your messages in proper detail - back later (supposed to be working at this time of day :-) )

It is good to be timid, but it is not an impossible job. First of all you need a long 4mm drill (obtainable from screwfix) and a set of ring spanners. (Ideally the drill should be a 11/64" long drill but they are virtually impossible to find these days,a 4.5mm may fit but it is a bit fatter than 11/64")

 

Remove the cable from, the top of the plug, (try not to drop the nut in the bilges) then slacken back the heater plug about one eigth of a turn to break the carbon seal and re-tighten, then slacken back one quarter of a turn an d re-tighten, repeat this at one quarter increments until the plug feels loose enough to remove by hand. If it is really carbonised in, it may need the assistance of a spanner all the way out. Finally remove the plug from the orifice taking care not to damage the heater probe. If the probe is missing from the plug it will almost certainly be coked into the heatwer orifice, and whilst there are theoretical ways of removing it, it usually entails removing the head. In such a case replace the broken plug and call an engineer.

 

The orifice now needs de-coking, using the 4mm long drill insert this into the orifice and twist it clockwise and anti clockwise, removing regularly to clear carbon from the drill. Take care not to drop the drill into the orifice, when manufactured the orifice has a seating at it's base to prevent this but it would appear that the seat often gets damaged and it cannot be guaranteed to be there at all. (one of the orifice seats in the head of my BMC is missing) when you are satisfied that all the carbon has been removed from the orifice, carefully clean any carbon from the plug, clean the threads if necessary and replace it, it does not need enormous force to seat it, and replace the cable. the other three plugs are a simople repeat process.

 

When the plugs are out it is always a good idea to check them, connect a 12 (positive) supply to the screw contact on the top and apply a negative to the body of the plug, the tip should glow bright red within ten seconds, if it does not the plug is U/S and needs replacing.

Edited March 11, 2010 by David Schweizer

[WotEver]

... shove a 12V supply from battery +ve on each one in turn, if you get a little spark then current is being drawn and the thing is most likely ok.

What great, simple advice!

 

Tony

[Priston]

What great, simple advice!

 

Tony

 

Unfortunately............ some of the glow plugs are NOT 12Volts and use a shunt to reduce the voltage to the glow plugs. In this case putting a 12 V charge across will merely ensure that the plugs will blow.

[alan_fincher]

Unfortunately............ some of the glow plugs are NOT 12Volts and use a shunt to reduce the voltage to the glow plugs.

 

Or some diesels I believe have them strung in series, with the 12 volts split across them.

 

Don't think that ever applies to a BMC though, does it, so what Snibs says is of course fine. An ammeter will indicate they are all fairly matched too.

 

Pretty certains that all 4 of our 1800 ones together draw well under 60 amps initially, so only 15 amps each. I thought the 1500 ones were considerably lower current, so am surprised it's thought they would blow fuses, trip trips, or melt plactic with a multi-meter on a 10 ams DC range, (in series with one plug at a time only, of course!).

 

I'm sure I have seen numbers for expected currents of old style versus new style BMC plugs, but can't recall where. If Tony brooks sees this I bet he knows - it may even be in his course notes ??.

[WotEver]

Unfortunately............ some of the glow plugs are NOT 12Volts and use a shunt to reduce the voltage to the glow plugs. In this case putting a 12 V charge across will merely ensure that the plugs will blow.

On BMC engines? You sure?

 

Tony

 

If Tony brooks sees this I bet he knows - it may even be in his course notes ??.

"Glow plugs tend to draw a high current. I have measured 75 amps dropping to 45 as they heat up on a BMC 1.8. Our BMC 1.5 draws about 40 amps dropping to 25."

 

About a third of the way down here: http://www.tb-training.co.uk/MarineE07.html

[Tony Brooks]

On BMC engines? You sure?

 

Tony

 

 

"Glow plugs tend to draw a high current. I have measured 75 amps dropping to 45 as they heat up on a BMC 1.8. Our BMC 1.5 draws about 40 amps dropping to 25."

 

About a third of the way down here: http://www.tb-training.co.uk/MarineE07.html

 

 

Just to add:

 

Modern glow plugs across Kubota, Mitsubishi & the BMC 1.8 seem to have a positive temperature coefficient in that a set of 4 will put a 75 amp clamp-meter off the scale for a fraction of a second and then drop to about 50 amps, so those draw a high current slowly dropping to about 12 amps per plug.

 

The 1.5 with the "pin" type plugs seem to draw a steady 6 amps per plug, thus about 25 amps for four.

 

The trouble with this is that very often/usually? the glowplug wiring is rather badly undersized so you get voltdrop and a corresponding decrease in current draw. The Beta we us eon the course with, as far as I can see, original wiring harness drops about 3 volts and the current is close to 30 amps than 50, but its a wiring fault.

[Mayflower]

Dear All,

 

Thank you all so much for your thoughts, insights, help and advice! In the end it was a fuel air-lock after all. We downloaded the service manual from the web, went to the boat today, checked the throttle and stop cables, checked the battery voltage unloaded, checked on-load voltage at glow-plugs and battery (surprised at the drop at the plugs, actually (12.4V at the battery unloaded, 12V under load, 9V at the plugs)). Bled the fuel lines (see below for the long version of that!), held in the heater for 30 secs and let go as we started to crank the engine (and we'd bought a Halford's 'power pack' charge-it-at-home battery which we popped in parallel with the engine battery) and after a bit of a cough and a splutter it eventually fired up beautifully! Very satisfying!!

 

It was nearly 10 degrees C today as well which was a great deal better than the sub-zero the last few times we've been there.

 

Thanks again, all!

[Mayflower]

The classic moment of the fuel line bleeding was him sat at the back one foot either side of the prop shaft, having undone the bleed screw on the top of the fuel pump, me flat on my belly on the top step with my arm down operating the lift pump, he says 'stop', I stop, he gets bleed screw over orifice and then that sickening 'tinkle, tinkle, plop' sound as it slipped out of his fingers. Me being smaller than him, it's me that strips down to wellies, jeans, t-shirt and rubber glove, backs into the angle between the battery cases and the engine, crouches in the bilge (still with 3 inches of water as we didn't want to use any power on the bilge pump until we'd tried to start the engine) and grovels around in the black slime in the drip tray (1 inch slime, 2 inches water, mono-molecular layer of black sump oil) for not only the bleed screw but also the 8mm ring spanner he managed to knock in after I'd found the screw!

 

And not a harsh word spoken by either of us!

[RobinJ]

... and grovels around in the black slime in the drip tray (1 inch slime, 2 inches water, mono-molecular layer of black sump oil) for not only the bleed screw but also the 8mm ring spanner he managed to knock in after I'd found the screw!

Oh! the memories.

(Still haven't found the 11mm spanner - I think that went water side?)

[WotEver]

(surprised at the drop at the plugs, actually (12.4V at the battery unloaded, 12V under load, 9V at the plugs

Tony B noted in Post #20 that the beta harness drops around 3V.

 

Tony

[David Schweizer]

The classic moment of the fuel line bleeding was him sat at the back one foot either side of the prop shaft, having undone the bleed screw on the top of the fuel pump, me flat on my belly on the top step with my arm down operating the lift pump, he says 'stop', I stop, he gets bleed screw over orifice and then that sickening 'tinkle, tinkle, plop' sound as it slipped out of his fingers. Me being smaller than him, it's me that strips down to wellies, jeans, t-shirt and rubber glove, backs into the angle between the battery cases and the engine, crouches in the bilge (still with 3 inches of water as we didn't want to use any power on the bilge pump until we'd tried to start the engine) and grovels around in the black slime in the drip tray (1 inch slime, 2 inches water, mono-molecular layer of black sump oil) for not only the bleed screw but also the 8mm ring spanner he managed to knock in after I'd found the screw!

 

And not a harsh word spoken by either of us!

Not sure which bleed screw you are referring to which you dropped. I have never needed to slacken either of the screws on the pump, and only ever slacken the blanking plug on the filter and two injectors. You should not need to actually remove any of them. AFAIK most CAV pumps fitted to the BMC 1.5 are self bleeding.